Fionna makes me feel represented
Throughout both season 1 and 2, I feel like Fionna is the character I relate to the most because of what I've been going through in my life. And I feel that's kind of saying something since normally I don't feel this way about ny of the Adventure Time characters. This is mainly because their experiences and personalities didn't always neatly fit into mine.
Like I share this sense of having an internal yearning to go back to your fantastical childlike world but have to adapt and grow up as an adult in the boring real world. Of trying, failing and sometimes succeeding in maintaining your relationships to be there for people in your life even when it feel like they aren't there for you. Of having to come to terms with trauma and mental complexes you only barely knew you had after they become set within you.
I think it's a shame that Fionna got alot of flak in Season 2 as I can safely she's now my favorite character in the entire Adventure Time franchise. What also helps is that I'm trans so I feel a sense of gender envy with Fionna where I want to be able to feel feminine like her. Also I like the idea that's a Sailor Moon fan from the first episode and she's that she's a bit of woman-child and girl failure just like me