Of course, he doesn't have any story-related artifacts, and it's much easier to lure him into the water, but the author still gave him 240 creatures, not 9999, which suggests that he probably intended for him to be defeated in some way.
Update: In principle, there's a way to lure him into Inferno (118, 59, 0), where he'll learn the Explosion skill. Attack him in the castle with a stack of harpies and, through summoning elementals, deplete his mana and Titan shots. After that, the computer shouldn't crash out of the castle after the non-ranged units are resurrected, so the harpies can be used to kill all his stacks. How realistic this option is, I don't know yet; it needs to be tested.