Baldur’s Gate 3 Abjuration Warlock Protoss Armor Guide

Arcane ward prevents HP loss equal to the number of active layers, and loses a layer each time a damage was prevented. Example: A Wizard with 4 layers of shield touches Karlach and takes 6 fire damage. Shields reduce that damage to 2, and 1 layer of shield is lost.
We can reduce incoming damage before shield negation by applying a Warding bond:
Now all incoming damage is halved, so we negate 2 damage per layer of shield. Intresting thing: Cleric should recieve another half of the incoming damage, but as of 06.08.23 game only transmits the damage Wizard takes after all reductions, resulting in abscence of harm to both characters:

Now we only need to add Agathys armor buff to get the retaliation damage going.

Any race, any stats, low dexterity is good since we want to get hit often. You need to start as a Fiend Warlock, make sure to pick Armor of Agathys spell. you can add Hex there as well to deal damage later. From level 2 go mutilclass into a wizard and pick any abjuration spell (Mage armor, protection from good and evil). As a bonus pick Longstrider ritual spell for free movement speed for your team.
Buff up, apply help from your cleric and ruch enemies like never before. Good item to buy from druids would be Gloves of Missile snaring, to help with damage negation from rangers.
Tip: In batlle you can run around and provoke attacks of enemies for 5-30 return damage without losing your reaction