Hey peeps i know this is obvious I just want to say why.I know this might sound weird but I like the fact that she was originally an antagonist and became good. It just makes her a more interesting character.Secondly I think it's awesome that she has a troubled past that haunts her adds to her personality and how awesome she is. She also has an wird past with the Ice King. THE ICE KING. They have very different personalities .And even though he annoys her,she still loves him for what he use to be.Finally she's a vampire in modern fiction and like old lore still burns in sunlight! So yeah what for reasons I stated and all the other reasons you can find on this wiki ,Marceline is awesome.