Liking Monster cock isnt what made her evil anon.
In fact, she is only evil from the Mewni perspective. her use of the Dakr Magicks is as natural as using its anti-thesis. blahblahblah darkness is equal to light, people of light scared of darkness, Kingdom hearts bullshit, she will be a secret boss in KH3
, Eclipsa was wrongfully imprisoned and her tales of using dark magiccs twisted over the years