Wait. . . there's a killer bunny? Lol. I never tried killing many bunnies, so never triggered him apparently lol. Is he one of Bellegar's pranks?
As for auras, I never much went out of my way to get auras. They always seemed so useless to me. I'd stack stat bonuses or + health/mana regen usually, or resists. Those always seemed more useful to me than a puny chance to do a puny amount of damage. Of course, I mostly played the game as a Battle Mage, so as long as I had mana and was alive, I could always call magic missiles and do a lot of damage - even if fireball was recharging.
With a Battle Mage character, well, fights don't last long. Either my enemies died quickly, or occasionally, I did lol. (Very late in the game, even the Battle Mage becomes a bit of a tank, but by then, my damage was so insane I usually instantly killed enemies 4 - 8 at a time with a single fireball, so the auras. . . not too useful by then either). Those auras seem like they'd be more useful on, say, a warrior type who has high resists and can just soak up the damage, while sitting there waiting for the auras to help him out.