Archer army

[MaroonMaurader]

The first round would be brutal. But say you make it through the first round with at least most of your army intact (which seems likely if you have 52% physical resistance).
If you have tactics 2, you can plant some guard droids in his weakspot before starting the battle, and that should encourage him to move on round 2 instead of summoning or attacking (70% chance I think). I'm going to guess it's something like a 50/50 whether he summons or mass-attacks on round 3 (and I'm just making that up; I have no clue what the actual odds would be); then another 70% chance that he moves on round 4 if you kept units in his weakspot when he moved. So maybe 1/4 times he'll go mass attack, move, summon, move in the first four rounds. When he moves you're in great shape - it's basically a free turn. When he summons, high-leadership, high-damage, high-crit., high-attack archers with quickdraw 3 boosting initiative should kill most or all of his summons before they ever get a chance to go, meaning it basically just wastes a turn for him and for you. And by turn 5, most of your units have stoneskin so you'd actually prefer he start using his mass-attack instead of summoning, as it lets you kill him faster instead of wasting time shooting his minions. At that point it's just a question of whether you'll have enough mana left when he finally dies to restore your casualties.

For this you want a number of things: defense, intelligence, and mana. So beyond the twinkling boots, scaly set, leather dress, and crystal ball, you want anything and everything that boosts those. However much damage you take in the first round, in the entire rest of the fight you're unlikely to take a fraction that much because after that, his attacks will be hitting 92%-resistance units.

With power of spirit 3, resistance 3, caution 3, and Titan's Armor, you're looking at a 22-point boost to defense right there. Add in another 8 points maybe from training dummies and whatnot plus the natural warrior skill, and you're looking at a 30-point boost to defense. You really ought to be able to come up with items giving another +10 defense for defense 40, meaning you're lowest-defense units are elves with defense 65. As his attack is 84, you're looking at something like a 1.6x multiplier to damage. His base damage is about 3.5k. Then consider you also have a 0.48x multiplier to damage thanks to physical resistance the first round; further add in the 20% decrease due to caution 3 (I think... if the 20% decrease adds to the physical resistance instead of multiplying it's even better, but I'm not sure how it works), and you're expecting about 2200 damage in the first round. Odds are good you'll take no more than 3000 damage over the entire course of the fight to your most-damaged unit (likely the elves).

With rage eater, Mag Rage, and Magical Flow, it's not that difficult to have an effective mana-pool after all's said and done of 225 mana if you're willing to wait long enough after the fight to get your rage all transferred to mana. That's enough to phantom the repair droids 3 times, and cast 6 level-3 resurrects. As the resurrects are being split between 3 units, that's 2 resurrects per unit. So you need each level-3 resurrect to restore about 1500 health. That's a high intelligence for a warrior, but nothing absurd - particularly given that you've got a number of equipment slots still open to shove with +int items if necessary.

That's my estimate. The easy way to test this, IF you happen to have a save-game with a hard difficulty warrior just before fighting k'tahu, would be to load that game, use the console to add the items you want, and try it (it might take a few shots to persuade him to summon on round 3 instead of using his mass-attack again, and to move on rounds 2 and 4). As I don't have that save game, it's not exactly easy for me to test.