I didn't know that! I thought that the first sacrifice (if you have nothing unlocked in the gro'goroth skill tree) unlocks the first node of gro'goroth which basically amplifies attack power or something!
Kalev does hit the optimal target but the fact that I can't increase his defenses and he loses half his HP from one attack really stresses me out :P he also takes my carrots and I need them for pies!