gremlin boss help

[loreangelicus]

Warrior on impossible difficulty, level 46, no-loss using droids and undead (black knights and bone dragons).

I guess I could have stuck with less units, or better yet units with good magic resistance (undead have no magic resistance, and droids are even 50% vulnerable to magic), but I wanted to complete the game with a full lineup, and I didn't want to waste time (going for a speed run as well, 7 days target) and gold buying new units and placing my favorite units in a castle/reserve.

Same tactic, stoneskin on black knights who hack at Zilgadis, everyone else kills towers, repair droids attack Zilgadis and guard droids/bone dragons defend when no towers are around, keep a friendly tower alive and kill Zilgadis asap.