Hyacinth (Oneiros)

Hyacinth's true power, unknown to even them until the events with Kass and Marian unveil it to them.  Turns out they're descended directly from Greek mythology, and possess the power of the oneiroi, the black-winged guardians of dreams.  Thanks to their partial human heritage, they possess the strength of both worlds: the creative, ephemeral manipulation of dreams and the subconscious, and the physical, organic body rooted in the real world.  This mix carries unintended consequences--Hyacinth's dreams end up manipulating reality.

This revelation shocks them to their core.  They've lived for so long completely unaware of this, and yet it explains so much.  But now that they realize they could be potentially manipulated and exploited for these abilities, they have to get them under control.  And what of the two intruders visiting them each night?  Are they taking advantage of them, too?  It's too much to process.  They break down.

They must keep themself safe, no matter the cost.  Even if it means shutting everyone out.