He doesn't fight to the last, but he uses the resurrection rune.
He plays defensively because I always rush him. (Delay means death for Orcs, or...?)
Magic is always different (you can't guess whether it will be light or dark).

And another question! Should I always take "Wrath of Fire" if it's offered, or...?

KITOBOI, don't take "Wrath of Fire," it's completely unclear why they even made that skill; it's detrimental. You might gain 100 wrath per unit attack, but you'll lose 150 from a counterattack, putting you in the negative!
Regarding the hero: choose either Tilseck or Haggeesh! Tilseck is a really strong hero! He's good at the beginning and at the end; it's easy to develop with him. He has machines at the beginning, and his warmachines are very powerful in the endgame! Definitely max out education and defense. If you max out both, by level 25, you'll be dominating in the main skills. Dwarves deal little damage because their attack is weak, and Orcs have wrath! Basically, you become almost invulnerable, even runes don't help much; the main thing is to get to him as quickly as possible, and then he's doomed! Orcs always have good morale, and their units will move more often than dwarves'. Don't take silence skills; they're not very effective, especially since a dwarf can learn any magic, but you might not guess what he'll learn! Also, dwarves are difficult to develop, so if you attack him quickly, you'll definitely destroy him! Good luck, take Tilseck, and give him a hard time! ;)