The girl. I guess she will be explained later, but for now... She obviously ain't normal, seeing she personally knows that even-more-obviously-abnormal white-haired red-eyed kid, but... In ep2 finale she appears and calls herself a ghost - which /seems to/ be a joke, as she lives in the hospital. Next episode, at the end as well, she talks with MC-kun and alludes to his God's Eyes after noticing something on a photo he took. Then, in 04, for some reason she gets moody and runs away from her hospital room after meeting the white-hair. THEN she sneaks off with MC-kun to watch a movie. I am seriously confused by her actions.
Kinda hard to answer that since the girl is anime original so I guess we have to wait and see how everything develops. I have theories on what can be happening but they are theories.
I'm liking how the original material is just slowly revealing hints about the characters with little of that actually being said by the characters themselves.
White is still being secretive by not really telling Leo much about her at all, he knows she has a brother and based on how emotional she got watching a movie about siblings, that there's definitely a sad story there.
We know that White genuinely likes Leo (whether as a friend or otherwise) and isn't exactly happy at whatever Despair-kun has planned for him without needing a scene of White telling Despair-kun that she doesn't want to hurt him or whatever.