the one that wants to destroy the worlds the most, the only kid that lives in the world of adult. IIRC he's the jaehwan that never grew up. the most stubbon of all, the most insecure yet powerful parts of jaehwan.
it kind of poetic really, since during the span of the series jaehan are kind of getting weaker(not as arrogant as he used to be) and start accepting people, meaning he kind of goes through the motions like adult do, getting further and further away from his first steps of his personal power, Question everything.and the kid version of him are the one that question the most.