Forget Shiva
If you are long lived and someday someone take out one of your eyes and keep it as a trophy within his city for 1000 years, would you not try to take it back?
Sure, 1000 years is a long time for a human. But for Niddhog it is not so long ago. Like if someone steal something important from you while you was 20 years old (like one of you eyes to keep it as a trophy) and with 40 you still feel the rage about this.
