This damage is too weak, and in the second half of the game, quality is preferred over quantity. Zerok is only useful at the beginning of the game, and in the later stages, he can only be used as a wall to block an overconfident enemy unit. Sleen is preferable in terms of offensive spells due to his "Chaos" spell, which usually hits everyone. Reaper is, of course, a beast, but you need to maintain his rage and, if possible, clear the area in one turn.