Editing creature abilities or adding new ones.

Death Harbingers have the ability – Deadly Grasp. Upon attacking, it always kills at least one unit in any enemy stack. Additionally, it removes all positive spells cast on the creature. In my opinion, this is an imbalanced ability. It needs to be reworked – a 50% chance to kill at least one creature in a stack, but only for units of level 4 or lower, and it shouldn't affect undead. Does anyone have suggestions on how to modify the ability as I proposed? And in this section, I suggest we discuss similar changes or the addition of new ones directly in the files, without using H5U.