Original Description

"Estas somos mi hermana (del alma) y yo, sesupone que entre mis amigos aventureros yo soy Marceline (aveces soy Cake) y mi Shimai es Fionna
Espero que les guste"


"Here we are my sister (of the soul) and me, between my adventurer friend I am Marceline (sometimes I'm Cake) and my Shimai is Fionna
I hope you like it"


Back in middle school, my friend group had an "adventure time rp thing" going on (quotation marks because in hindsight, it was more of a kinning thing before kinning was a widespread thing), and I was Marceline cause I kinned Marceline but I also roleplayed as Cake because my best friend kin Fionna.
As for the "Shimai"... I just googled translated the word sister in Japanese cause I was a weeb but didn't pick on yet that Onee-chan meant sister.