Inscryption Devil’s Play and Dark Offering

To get Dark Offering you simply need to get both halves of the Broken Obal
They can both be purchased in the bottom right slot of Grimora’s trader for foilAfter you have both cards, simply place them in the same orientation as above in a fight and you will get the Ancient Obal. If you can’t do it in a fight use the training dummy on the second floor of the tower.

After you have the Ancient Obal head down the stairs in Grimora’s crypt and interact with the coffin in the corner

You can then go retrieve the Bone Lord’s Horn and Femur

First assemble a deck that contains these cards
A Bone Heap an Energy Conduit and the Bone Lords Horn

Aswell as 1 more conduit card, it doesnt matter which one you choose

After that you can fill the rest of your deck with anything, extra’s of your cards, skeletons, or mox’s make good picks though

Once you are in the fight you don’t need to worry much as none of the enemies actually attack.
Skip your turn until you have all of the cards you need then place them in this order
Misc. Conduit -> Bone Lord Horn -> Bone Heap -> Energy Conduit
(you can use stim wizard instead of the bone lord horn and bone heap but you got the horn so you wanna use it)

Since you already got Dark Offering and Devil’s Play, this part is really easy!
All you need to do is wait at the dock for a short bit and a tentacle will rise out of the waterInteract with the tentacle and then head to the towerOn the top floor of the tower there is a room to the right, go into that room and wait for a bit again
a tentacle will pop out of the bathtub

Interact with that tentacle and it will go down and come back up with a card

Any other cards you want can be found in card packs, if you are unsure what cards you are missing the traders room on the bottom floor of the tower has a book you can check that shows you all your discovered cards