User blog comment:Jkphantom9/Some Ruby figure fun, I presume?/@comment-186.188.68.63-20140312165401/@comment-6830001-20140312211025

Ruby as Eren... I don't imagine her in titan form... Or at least not in a cute form...

It's hard for an anime now not to use tropes since everything has somehow been done at least once... And Ki isn't only an anime concept if I remember well so it's normal it can inspire them as well.