Persona 3 Portable Secret Boss Fights Guide

Seeing that I am writing more than one method to beat the same fights, I think it would be appropriate to see how this guide will turn out. I will be writing one whole pass through both fights with Low Completion and with everything unlock to the player’s disposal.

As such, if one simply wants to look at one method or the other, it is quite easy to do so in one click.

At the start, I will be explaining the general rules of both fights. What their gimmicks are, and what to expect from them.

Next, I will be explaining optimal ways to grind the needed materials that is universal to both versions. If there is a difference between versions due to the limitations of the former, I will put a note on this.

As for each version, I will be explaining in full detail what one needs to do to replicate what I have on my save. This includes fusion paths and whatnot (A note, when I write Bi-fusion recipes, levels will not be included unless it is required for skills. As for Tri-fusions, it will be included due to how fusion works. It is a suggestion to completely follow the prescribed levels since this is what I used). And some optional things possible between steps. A demonstration of the fights shall be at the end of each versions.

For context, “Low Completion” implies that I do as little optional content as possible such as skipping non-auto s.links, skipping many requests (I went into the assumption that someone managed to do at least Request 29 for Machine Core. Required to make Nata Taishi and ergo, Alice), and only started to think of beating the secret bosses in January. In summary, this guide will be showing the best possible way to beat Elizabeth/Theodore and Margaret with the least amount of optional content done as possible.

As for “Optimized”, it is quite simple. It is simply having everything possible at the player’s disposal. All s.links done, all possible equipment usable, all personas usable, all possible items usable and and more. This portion of the guide will simply show off the best possible general method I could think of to defeat the secret bosses given that the player has access to everything.

These two have identical fights under the hood. They have the same HP bar (20,000 HP). They both have two moves per turn (Ergo, debuffs wears off faster than buffs for them). They have the same prerequisite (Unlocking Monad in whichever method one does, the request for this fight will automatically be available).

Same with rules and these are:

• Do not null/drain/repel the skill they will use next (Counter passives and nullification of ailments are an exception to this). Thanks to this, any persona that nulls/drains/repels any phys element innately at all is not allowed (Such as Shiva, Mara, Siegfried, and more).
• Do not go beyond 100 turns to beat them (This is their turn limit, their pattern when they hit this limit will be, more or less, random between using skills from the persona given in the pattern they used last, healing, or using Megidolaon with Pixie/Metatron)
• Do not use Armageddon unless this will be the finishing blow (They will instantly spam Megidolaon if this is not done properly. Armageddon is required to beat this fight)
• They will heal for the first time when their HP bar is reduced by half (On subsequent turns after this, they will heal when their HP is reduced by 70% indefinitely until they hit the turn limit)
• They will take 50% more damage when you use a skill that is the opposite of the element they used last (I tend to call this property “Vulnerability” but some also calls it “Half-Weakness”. Fire to Ice as Elec is to Wind). Must also be of note that they will drain the element they used last in their pattern. So keep that in mind.

The only differences are the personas used. What Elizabeth uses have an analog persona for Theodore. These personas correspond to what move they do. They follow a single pattern:

• Fire (With Surt/Uriel. Nulls Strike and Insta-kills, Drain Fire, Vulnerable to Ice)
• Ice (With Jack Frost/Gabriel. Nulls Pierce and Insta-kills, Drain Ice, Vulnerable to Fire)
• Elec (With Thor/Michael. Nulls Slash and Insta-kills, Drains Elec, Vulnerable to Wind)
• Wind (With Cu Chulainn/Raphael. Nulls Pierce and Insta-kills, Drains Wind, Vulnerable to Elec)
• Light (With Metatron/Sandalphon. Nulls Magic)
• Dark (With Alice/Lilith. Nulls Magic)
• Ailments (With Nebiros/Abaddon. Resist all)
• Almighty (With Masakado/Beelzebub. Nulls all)

(Vulnerable in this context means the mechanic with 50% more damage applies to these personas. If it is not mentioned, they are susceptible to the unmentioned elements but will not do much damage).

They do not break this pattern except for special circumstances such as breaking their rules (Instantly getting Megidolaon) or if they heal due to reaching the needed amount of damage to proc this (With Pixie/Metatron).

It is required to use the fusion spell Infinity to survive through the Almighty turns with Masakado/Metatron. Or alternatively, you can tank this using Endure + Enduring soul once if you ran out of Infinity to use.

Seeing as they heal indefinitely when they go below 6,000 HP, Armageddon being used for the finishing blow is required. There is no other possible way in the game to deal more than 6,000 damage in one turn in this fight (Not in P3P, at least. Only in FES).

With this in mind, generally the best course of action is to exploit Vulnerabilities in this fight. So a persona or two to do this is highly recommended (Highly recommended to use Messiah due to Magic Skill Up and another persona of your choosing). Some repels from High Counter will also help (But do not be reliant on this, its 20% proc rate is not very reliable). It is much better to attack during the onslaught instead of relying on the High Counter skip

It is best to note here that there is a special quirk with resists. The resists from persona skills/innate resists stack with resists from equipment (Such as the Armor of Light). This is an important fact to keep in mind to keep damage to a low as much as possible. This defense also works with Divine Pillar. It is imperative to keep this info in mind when fighting them.

Continuing on with Margaret, her fight is a tad more complex (It is more phase-based). As such, it is best to speak of this fight per phase (Although it is possible to skip some phases if you do enough damage, much more common to do). But first, we must mention her rules (It is similar to her siblings).

These are:

• Do not use Armageddon unless it will kill (But this is not required to be done in this fight. You can kill her without the fusion spell)
• Do not deal less than 5,000 damage to her per phase (This is a Megidolaon lose condition if not met, a phase lasts by 10 turns)
• Do not equip the Omnipotent Orb on any member (This is a lose condition as well. But keep in mind, actually nulling/draining/repelling her attacks is allowed. Only the equipment specifically is not allowed)
• She has a 50 turn limit (She will instantly end the fight with a Slime using Megidolaon. If, for some reason, you use Infinity when this occurs, she will use Diarahan afterwards).

Some more little things to keep in mind. Similarly to Elizabeth and Theodore, she also has 2 moves per turn (So debuffs wearing off more quickly also applies here). But what is not similar, however, is the amount of health she has (30,000 HP. Ergo, you need to do around 6,000 damage per phase if you wish to not use Armageddon against her).

With that, we must talk about her fight per phases. These phases have a certain theme attached to it in terms of the moves used and the personas used as well.

First phase (Phys Heavenly Kings)
In this phase, she will be using the 4 Heavenly Kings (Jikokuten for Slash attacks, Zouchouten for Strike attacks, Koumokuten for Pierce attacks, and Bishamonten for all of these combined). As a general rule, whatever phys element she uses last will be drained. She will Power Charge if she gets a crit (A special case, if she gets a crit on her 2nd move of her turn, she will use Power Charge using three out of four Heavenly Kings. Bishamonten will not be used, luckily. And so, you need to pay attention to what persona she used to Power Charge in order to know what phys element she will drain). In addition to her shifting phys resistances, she also nulls every magic element during this phase. Ergo, there is only 3 ways to damage her. And that is using Physical spells that will not be drained, Almighty spells in general, and lastly, Elemental break spells being combined with the element it breaks (Although this is generally unreliable. The break effect will run out whenever it is her turn instead of three turns. As such, it is only usable in a specific setup. This will be explained later).

Second phase (Magic/Ailments/Phys/Insta-kills with added personas from P4)
In this phase, she will be using two out of the 4 added personas from Persona 4 (Mokoi and Neko Shogun). Mokoi will generally use Stagnant Air and Ailments (Rage, Charm, and Poison). And Neko Shogun will generally use a multitude of skills such as AoE magic attacks, Insta-kills, and Physical skills (If a character is enraged. She will focus on these characters using said Physical skills. Otherwise, she will refrain from using any Physical skills at all). She is vulnerable to all kinds of attacks in this phase (Except Insta-kills, of course).

Third Phase (Magic Mitamas)
In this phase, she will be using the 4 Mitamas to deal AoE damage to the party. But if one of your members has a vulnerable weakness (Such as not patching it using the Armor of Light), she will focus on said member. She will not be vulnerable to any attacks except Almighty and the opposite of the element she used last (As a reference, Ara Mitama is vulnerable to ice, Nigi Mitama is vulnerable to fire, Saki Mitama is vulnerable to wind, while Kushi Mitama is vulnerable to elec. More or less, the opposite of the element she uses last is what she will be vulnerable to in that turn). The break strategy mentioned in the first phase can also apply here. That will be elaborated later on.

Fourth Phase (Just the Moirae sisters)
In this phase, Margaret utilizes the 3 Moirae sisters (Clotho, Lachesis, and Atropos). The way she uses them aligns to their job in myth. She uses Clotho to prepare with Power Charge/Mind Charge (Threading of the string). She uses Lachesis to do a handful of moves such as -karn spells, Marakunda, Evil Smile and if this ailment hits, Ghastly Wail (Determining the length of the string). And finally, she uses Atropos to unleash a Mind Charged Megidolaon and a Power Charged AoE Phys skill (Cutting of the string, ending one’s life). This is done in sequence so this pattern will not be broken. She is vulnerable to all kinds of attacks during this phase. Interestingly, Clotho’s Power Charge/Mind Charge combo will chain into her final phase. Which comes to….

Fifth Phase (Copy her siblings)
In this phase, Margaret will be using Elizabeth’s personas. (Resistances included). With this comes her gimmicks such as Vulnerability/Half-Weakness. As for what persona she uses, it depends on the skill used last by the party. If one used a healing spell last, she will heal as well. If one uses a magic spell, she will use that as well. Oddly, if you use a buff, she will use Mahamaon. If you use a debuff, she will use Mamudoon. Anyways, given these restrictions, it is not advisable to enter this phase while in a party (Either kill her before she reaches this phase or use Armageddon if you did not manage to do so).

Ok so, to lower expectations. It must be noted that doing these fights will demand multiple hours in grinding the needed materials for these fights. So it must be expected that this process will take a while to do. Even still, these methods will be the most certain method to grind said materials.

So, we need these items for use for the Low Completion portion of this guide. I will be listing how much material is needed here. And also crunch the numbers on the needed gems for easier reference on how much is needed to be grinded in a later section. If these are skill cards that is from personas, I will list the needed persona and the level it gives the needed card.

Low Completion items:

• 10-12 Infinity (48 Malachite, 48 Pearl)
• 1 Armageddon (99 Malachite, 10 Ruby)
• 10 Fierce Sutra (10 Amethyst, 10 Aquamarine)
• 20-30 Beads (Half of this can be satisfied by a Tartarus Boss in Adamah upon its defeat, 30 Opal, 30 Garnet if one grinds it manually)
• 10 Magic Mirror (10 Sapphire, 10 Topaz)
• 10 Attack Mirror (10 Diamond, 10 Opal)
• 50 King of Wands (100 Onyx, 50 Garnet)
• 50 King of Coins (100 Onyx, 50 Aquamarine)
• 50 King of Cups (100 Onyx, 50 Turquoise)
• 50 King of Swords (100 Onyx, 50 Amethyst)
  (Please keep in mind that these amounts can be reduced significantly using Stat Inheritance)
• 10 Homonculus (If you could afford more, take more. I suggest doing the Luck door of Vision Quest to get 20 free. There is also a rescue request that gives 10 of these in January. 10 Diamonds, 10 Sapphire)
• 2 Resist Slash card (2 Sapphire, 2 Diamond)
• 3 Resist Strike card (3 Sapphire, 3 Diamond)
• 5 Resist Pierce card (5 Sapphire, 5 Diamond)
• 1 Resist Fire card (2 Sapphire, 1 Ruby)
• 1 Resist Elec card (2 Sapphire, 1 Ruby)
• 1 Null Poison card (Barong Level 56, 1 Turquoise)
• 1 Ice Boost card (Jack Frost level 14. 1 Turquoise, 1 Opal)
• 1 Ice Amp card (Titania level 55)
• 1 Elec Boost card (Take-Mikazuchi level 31, 1 Turquoise, 1 Topaz)
• 3 Mind Charge card (Atropos level 59)
• 1 Tarukaja card (Forneus level 8)
• 2 Diarahan card (Bishamonten level 66)
• 1 Vorpal Blade card (Susano-O level 85)
• 1 Auto-Tarukaja card (Oumitsunu level 34, 4 Turquoise)
• 1 Auto-Rakukaja card (Genbu level 33, 4 Turquoise)
• 2 Regenerate 3 card (14 Aquamarine)
• 1 Arms Master card (10 Pearl)
• 10 to 15 Growth 3 card (Depends if you want to use personas for 5 cards or just the antique store, Jatayu level 59. This will be important later)

(How the cards will be used shall be explained in the Persona Builds portion of the Low Completion part of the guide)

Low Completion Equipment:

• 4 sets of Armor of Light
• 4 sets of Shoes of Light
• Indra/Vayu bracers (Depends if you want Ken or Yukari as a healer for Margaret)
• Elec Bracers
• Ice Bracers
• Tome of the Void
• (Any weapon for the MC. Preferably, Khakkhara by weapon fusing Atavaka or Vel Vel Muruga by weapon fusing Kartikeya for the female protag. Although the latter requires going for more than Request 29 and a Liz/Theo date, at that. Meaning, it is very easy to miss if you miss only one of these dates. For the male protag, there is less options due to his ult weapon being locked behind Max Rank Star with Helel. Best possible for him is Excalibur which is from Monad golden chests. Or Deus Xiphos which is made from weapon fusing Michael. Either way, it is possible to simply buy the best regular weapon Officer Kurosawa sells and it will be sufficient)
• Any weapon for Mitsuru (Snow Queen Whip by weapon fusing Skadi is best. If not possible, Longinus from Monad golden chests works. If not possible altogether, the best possible regular weapon from Officer Kurosawa is enough)
• Any weapon for Yukari/Ken (Ken has a bit of an advantage since his ult weapon only requires Shiva for Pinaka while Yukari requires Max Tower Chi You for Quintessence Bow. However, his Darkness weakness can be a detriment to Margaret. Yukari’s best possible weapon is Maki’s Resolve from Monad gold chests or Sarnga, Vishnu weapons fusion. But anything should be sufficient for these two)
• Any weapon for your last member (Anyone can be picked here. Although Akihiko is probably best due to debuffs. His best weapon would be Evil Gloves from Mara. But anything is fine. Junpei can use Masakado’s Katana but that requires more requests. Anything is fine for him as well. Aigis and Koromaru is probably the least helpful. Aigis can use a generic Tower persona for weapons fusion to remove her weakness but she does not offer much in the fight. Koro cannot nullify his weakness at all without offering anything. So I would avoid these two)

There is definitely no expectation that this method will not be grindy. It definitely will take awhile to do this. So be warned.

So, we need these items for use for the Optimized portion of this guide. Like with the Low Completion portion of this guide, I will be listing how much material is needed here. And also crunch the numbers on the needed gems for easier reference on how much is needed to be grinded in a later section. If these are skill cards that is from personas, I will list the needed persona and the level it gives the needed card.

Optimized items:

• 10-12 Infinity (48 Malachite, 48 Pearl)
• 10 Best Friends (20 Malachite, 20 Topaz)
• 20-30 Cadenza (60 Malachite, 30 Amethyst)
• 1 Armageddon (99 Malachite, 10 Ruby)
• 10 Fierce Sutra (10 Amethyst, 10 Aquamarine)
• 20-30 Beads (Half of this can be satisfied by a Tartarus Boss in Adamah upon its defeat, 30 Opal, 30 Garnet if one grinds it manually)
• 10 Magic Mirror (10 Sapphire, 10 Topaz)
• 10 Attack Mirror (10 Diamond, 10 Opal)
• 70 King of Wands (140 Onyx, 70 Garnet)
• 70 King of Coins (140 Onyx, 70 Aquamarine)
• 70 King of Cups (140 Onyx, 70 Turquoise)
• 70 King of Swords (140 Onyx, 70 Amethyst)
  (Please keep in mind that these amounts can be reduced significantly using Stat Inheritance)
• 10 Homonculus (If you could afford more, take more. I suggest doing the Luck door of Vision Quest to get 20 free. There is also a rescue request that gives 10 of these in January. 10 Diamonds, 10 Sapphire)
• 1 Resist Slash (1 Sapphire, 1 Diamond)
• 1 Resist Strike (1 Sapphire, 1 Diamond)
• 1 Resist Pierce (1 Sapphire, 1 Diamond)
• 1 Resist ice (2 Sapphire, 1 Pearl)
• 1 Absorb Slash (Helel level 96)
• 1 Absorb Strike (Abaddon level 75)
• 1 Absorb Fire (Skadi level 88)
• 1 Absorb Elec (Kartikeya level 77)
• 2 Absorb Wind (Ananta 83)
• 4 Null Poison (4 Turquoise, Barong level 56)
• 2 Null Charm (2 Turquoise)
• 3 Unshaken Will (Asura level 93)
• 3 High Counter (Siegfried level 67)
• 1 Fire boost (Hua Po level 25, 1 Turquoise, 1 Garnet)
• 1 Fire Amp (Kumbhanda level 63)
• 1 Elec Boost (Take-Mikazuchi level 31, 1 Turquoise, 1 Topaz)
• 1 Elec Amp (Odin level 66)
• 1 Ice Amp (Titania level 55)
• 2 Rakunda (Queen Mab level 30)
• 1 Provoke (Nekomata level 11)
• 4 Mind Charge (Atropos level 59)
• 1 Power Charge (Setanta level 23)
• 1 Diarahan (Bishamonten level 66)
• 1 Salvation (January Rescue reward, Vishnu level 87)
• 2 Regenerate 1 (Neko Shogun level 23, 2 Aquamarine)
• 2 Regenerate 2 (10 Aquamarine)
• 3 Regenerate 3 (Norn level 70, 21 Aquamarine)
• 1 Invigorate 1 (Kikuri-Hime level 57, 1 Amethyst)
• 1 Invigorate 2 (5 Amethyst
• 1 Invigorate 3 (7 Amethyst)
• 2 Spell Master (Lucifer level 96, 10 Diamond)
• 1 Ailment Boost (Mother Harlot level 79)
• 1 Weapons Master (December Rescue Reward)

(How the cards will be used shall be explained in the Persona Builds portion of the Optimal part of the guide)

Optimized Equipment:

• 4 sets of Armor of Light
• 4 sets of Shoes of Light
• Barbaric Bracers/Divine Pillar (For the protagonist)
• 3 Frenzy Beads (Chest in Tartarus 35 floor)
• Lucifer’s Blade from, well, Lucifer fusion weapon for the male protagonist or Vel Vel Muruga from Kartikeya fusion weapon for the female protagonist.
• Masakado’s Katana from, well, Masakado fusion weapon for Junpei
• Evil Gloves from Mara fusion weapon for Akihiko
• Pinaka from Shiva fusion weapon for Ken

As you have noticed, An abundant amount of Growth 3 cards is required in both methods of this guide. This is because of how to efficiently grind needed materials from personas such as Skill Cards or Heart Items. As such, it is important to note how to grind efficiently using Growth 3. Firstly, it must be noted where to get Growth 3. And this is either a card to be bought from the Antique shop for 7 Opal or alternatively, from fusing Jatayu of the Sun arcana (Gives the card at level 59). Notably, if you maxed Sun arcana s.link, fusing Jatayu will immediately net you a Growth 3 card thanks to S.link Exp bonuses. But if you did not do this S.link at all, you can turn Jatayu into a fodder for his Growth 3 skill card itself. Which brings us to the next part.

How to turn a persona into a Skill card/Heart item fodder. It is quite simple. Attach Growth 3 into the persona with the needed card/heart item in question. After doing so, grind until they are just before leveling up to obtained their needed material. Now, immediately go back to the entrance, register the fodder persona, save, and fight an enemy to obtain the needed material. After doing so, discard the fodder persona from your stock, reobtain said fodder persona from the compendium, save, and repeat the process. Doing this to multiple personas with important skill cards or heart items is a great idea in order to maximize efficiency to grinding. For personas that gives very important heart items (Like Messiah with Armor of Light/Shoes of Light/Aura Dog Suit/Soul of Athena/Swan Legs/Omnipotent orb), this is more or less required since Messiah himself is a very powerful persona that’s always built on (With that, fusing him over and over again will not bode well with effort put in). This process is quite expensive, however. using the Messiah example once again, if you properly built him before grinding equipment from him, he will cost around 3,000,000 Yen per summon if on Hard/Maniac mode. And that is going to cost you immensely. Which brings us to the next part

How to grind money efficiently. It is quite simple once again. It is simply running throughout Tartarus Block 5 (Harabah) or 6 (Adamah).Thanks to P3P not making members pocket money they find anymore, simply making them spreading out floors and finding chests for you will net you many amounts of money. It is that simple. Now you can also do this in Monad if one is hunting for Monad gold chest weapons. But this is less than ideal if you are avoiding that (Because not every shadow will be running away from you). Seeing that they are also picking up item chests, it is possible that you will net Beads or Balms of Life from the chests. Or even better, Homonculus/Attack Mirror/Magic Mirror from golden chests in these blocks. These will reduce grinding for gems significantly. Which brings us to the next part.

How to grind gems needed for the needed materials. Now this is a very complex question considering that there is a lot of needed gems for things such as items, fusion spells, skill cards and whatnot. I am well aware how these gems are available when beating the revamped Full Moon bosses doors from Vision Quest. These are mostly reliable in giving gems. It seems that it could give 20 of the gems it gives the first time you get said gems from these doors (It is possible to get fusion spells or various passive skill cards instead if you do a prerequisite within the fight, but these prerequisites are not as well understood. So these are not reliable to aim for). Subsequently, it will only give 5 per fight or possibly even only 1 in some cases. Not all gems are obtainable this way as well. Seeing that conundrum, I will simply recommend grinding these if you can fight these doors very quickly and the gems it does give is obtainable by this method. These gems are (Either 20, 5, or 1):

• Priestess: Opal
• Emperor/Empress: Garnet
• Hierophant: Sapphire
• Lovers: Diamond
• Chariot/Justice: Turquoise
• Hermit: Topaz (This is the one where I noticed I’m only getting one gem. Oddly, only when Akihiko is in the party. I believe it is because he nulls elec. So best to fight this boss without anyone nulling/draining/repelling elec)
• Fortune/Strength: Pearl
• Hanged Man: Ruby

If this is somehow not your fancy, I compiled the best places to grind these gems and crunched the numbers of how much you need to grind per guide section. Might be helpful while grinding Malachites and those other gems that does not appear in Vision Quest such as Onyx. And these are:

(Low Completion)

• 400 Onyx (25-36 Tartarus floors)
• 147 Malachite (Any floor, but is likely going to be raised while grinding Onyx)
• 65 Garnet (Constant throughout Yabbasshah, Tziah, Harabah, and Adamah. blocks 3 to 6)
• 61 Turquoise (Constant throughout Arqa, Yabbasshah, Tziah, and Adamah. Blocks 2 to 5)
• 60 Amethyst (25-36 Tartarus floors)
• 58 Pearl (165- 179, 202-213, 237-261 Tartarus floors)
• 30 Diamond (229-239 Tartarus floors)
• 26 Opal (Whole of Tziah, 4th block of Tartarus)
• 24 Sapphire (Whole of Adamah, 6th block of Tartarus)
• 24 Aquamarine (25-36 Tartarus floors)
• 12 Ruby (Whole of Adamah, 6th block of Tartarus)
• 11 Topaz (Whole of Adamah, 6th block of Tartarus)

(Optimized)

• 560 Onyx (25-36 Tartarus floors)
• 227 Malachite (Any floor, but is likely going to be raised while grinding Onyx)
• 123 Amethyst (25-36 Tartarus floors)
• 113 Aquamarine (25-36 Tartarus floors)
• 101 Garnet (Constant throughout Yabbasshah, Tziah, Harabah, and Adamah. blocks 3 to 6)
• 78 Turquoise (Constant throughout Arqa, Yabbasshah, Tziah, and Adamah. Blocks 2 to 5)
• 49 Pearl (165- 179, 202-213, 237-261 Tartarus floors)
• 40 Opal (Whole of Tziah, 4th block of Tartarus)
• 30 Topaz (Whole of Adamah, 6th block of Tartarus)
• 25 Sapphire (Whole of Adamah, 6th block of Tartarus)
• 23 Diamond (229-239 Tartarus floors)

(Please note that these figures are the worst case scenario wherein one started from scratch 100% without any prior items. The amount may be lowered depending on one’s situation, mostly if one obtains some of these materials naturally or utilizing Stat Inheritance)

How to grind EXP. It is quite straightforward. One must unlock Monad by doing request 53 (Defeat the Reaper). And if one reaches the last floor of Tartarus before 1/31, Monad should be unlocked. Seeing that this place has very tough enemies, it is imperative to create a persona made for grinding. This is my recommendation if this is at the start (Optimized, you can make whatever. This is more for Low Completion. But it could be useful until one can create a persona of your own)

Step 1: Obtain an Arms Master card
As the Required Material (Low Completion) lists, this will be obtainable in the Antique shop for 10 Pearl.

Step 2: Obtain a Vorpal Blade card
Again, the list says this will be obtained from Susano-O level 85. You can make an argument to use Susano-O himself for grinding. However, I believe this will be more worth it in the long run.

Step 3: Fusing Chernobog
It is a simple recipe. We will aim for Ose + Bishamonten for the recipe for Chernobog since Ose will obtain Cool Breeze at level 49. As for Bishamonten, we need to give him skills to pass to Chernobog first. So the first step is to create Bishamonten using Kali (55-58) + Ose (44-49) + Neko Shogun (19). Pass on Apt Pupil. And if your Ose has Cool Breeze already (Very likely), managing to pass that on as well will be beneficial.

Resummon Ose once again and fuse it into Bishamonten to create Chernobog. Pass on Apt Pupil and Cool Breeze. And if you manage to obtain Maragidyne from Bishamonten, that would also be lovely. It is not required so do not worry if you did not manage to do it.

After fusing, add in Vorpal Blade card and Arms Master card (If you did not opt to get it via fusion) to skills such as Null Slash and Mamudoon. Blade of Fury can be replaced by Null Wind when he learns this. And voila, a grinding persona that can beat the majority of enemies in Monad.

When grinding, please remember to be in great condition while doing so. This grinding persona takes advantage of the fact that Vorpal Blade’s damage is doubled while in great condition.

I will make this as extensive as possible. And offer some ways to shortcut grinding. I suggest to read my previous General Fusion Guide for P3P. It will help tremendously in understanding some mechanics in fusion. Such as Stat Inheritance. This is a general tip to reduce grinding stat cards a decent amount. It is simple, every time the persona that is needed (Indicated as the persona in the step name) is fused, add in some stat cards, preferably until it is fully boosted. These stat cards will be inherited to the next ingredients but it diminishes every step by half after the first step. So every now and then, one can add more stat cards to continue the chain.

And of course, register the persona after fusion because it will be used in chains to take advantage of stat inheritance. But keep in mind, this will make them expensive to resummon afterwards. So majority of the time, one would be grinding money between steps if this is what you want to do.

Keep in mind that these were done on a save with all s.links completed so you will still see S.link rank bonuses on my ingredients. But this is taken account in these recipes. Hence, the levels being written out.

First Step: Create Garuda
Garuda’s very decent resistance spread against physical is why I opted to choose him for this. But he does need some skills that do not have skill cards for him to be effective. As such, we need to obtain these skills first. Lachesis (51 for Evade Elec) + Mothman. Inherit Evade Elec.
Next is to fuse Garuda himself. The recipe we need is Kingu (46-51) + Titania (48-53) + Abaddon (68-74). Inherit Evade Fire and Evade Elec.
(There is a possible way to save some skill cards in this. If you manage to inherit Null Poison from Kingu in level 49. And also, Mind Charge from Titania, who has it innate. The former will be useful for the next step while the latter helps Garuda and the next step. It is of one’s discretion if this will be done. Skill cards are always there as fallback)

Second Step: Create Anubis
This is only one step. Garuda (69-70 for High Counter) + Eligor (31-35) + Cu Chulainn (40-47). Very simple. And if you opt for using Stat Inheritance, all of the stats will be inherited. Inherit High Counter (And as stated before, if you opted for Null Poison from Kingu in the last step, inherit Null Poison. Same with Mind Charge from Titania).

Third Step: Create Dionysus
Another one step. Anubis + Nigi Mitama. Inherit High Counter (In the screenshot shown, I demonstrated what utilizing stat inheritance will look like).

Fourth Step: Create Jikokuten
This will require two steps due to needing two skills to inherit. First up is Garuda (69 for High Counter) + Inugami. To create a Narasimha. Inherit High Counter (If you boosted Garuda, this Narasimha will be boosted as well).
Next is to create Jikokuten himself. Valkyrie + Narasimha. Inherit High Counter and Evade Wind (Same thing with stat inheritance applies here).

Fifth step: Create Messiah
Now this will be the star of the show. Due to Magic Skill Up, he will be doing the most damage out of anyone else with magic. And so, it is imperative to give him the best possible damaging skill available. Due to Low Completion’s rules, the only thing that is possible to use is Nifflheim (Surt, Odin, and Norn are locked behind optional s.links). This will be the longest chain among the five. First step is Decarabia (52 for Evade Ice) + Slime. Inherit Evade Ice.
Second is Legion + Slime. Inherit Evade Ice once again.
The first ingredient is made. Now on to the other one. Skadi (86 for Nifflheim) + Ares. Inheriting Nifflheim (It is also possible to inherit Ice Amp as well but I do not recommend this due to how hard Thanatos is to fuse).
Next is to downfuse. Pazuzu + Lilim and again, inherit Nifflheim.
And finally, Vetala + Mokoi, inherit Nifflheim.
And the second to the last step (Kinda), Lilim + Pixie + Narcissus + Nata Taishi. Inherit Nifflheim.
All one needs to do in this point is to fuse Thanatos. Ghoul + Pale Rider + Loa + Samael + Mot + Alice. But I think it is a good idea to downfuse Nifflheim to the others beforehand and eliminate as much Mudo spells as possible (Apart from Die For Me! since it is non-inheritable). Inherit Nifflheim.

And finally, the last step. Orpheus + Thanatos, inherit Evade Ice and Nifflheim.

And voila, all the personas are now fused with the needed skills that cannot be given with skill cards.

Now that we fused the needed personas, now to actually build them. But first, I will emphasize Growth 3’s importance in this step. As much as possible, we want to grind the least amount of stat cards as possible. So the idea is to grind these personas to level 99 assuming its stats were not boosted from other means beforehand like Stat Inheritance. In these screenshots, I already had multiple stat cards at hand so I boosted these without any leveling up at all. So keep that in mind.

Anyways, these are the skills needed. The skill cards in the Materials section all fulfill the needed amount of cards.
Garuda:
Anubis:
Dionysus:
Jikokuten:
Messiah:
(Note that they all have Resist Pierce. So I suggest you put Growth 3 instead of Resist Pierce, grind them to 99, and put Resist Pierce at the end.)
(Messiah being essential for Equipment needs to be noted so you might want to refrain from boosting his stats to lessen the amount of money needed to resummon. At the very least, up until you manage to grind all needed equipment from him)