It is fun, they'd agree on that. She gives her all to everything and has a perfectionistic and competitive streak that would make the challenge both fun and infuriating to her. The best kind of fun! The kind where she wants to scream afterward and spends hours practicing because she will best that twerp, yes, she will.

To be fair, it's complicated. Most of her violence is constrained to her little fantasy worlds (which is still very much not okay and needs to be addressed as the power abuse it is) and the result of severe grief. Her actual in the real world murder plans are limited to people she thinks are responsible for said grief, so at least she's not like... pro-actively murdery.

She could easily end up in a bad place, but if she gets some help she's far from irredeemable. Just one of those 'morals are for children' types who thinks the world is cruel and you have to be cruel back.