





Kris is obsessed with the past, Susie is obsessed with the present, Ralsei is obsessed with the future.
Kris is somebody who misses their childhood and is obsessed with righting a wrong that they did, to the point that they neglect their present health. The fact that they now have taken poisonous seeds means that they don't think they have much of a future as well. Chapter 3 even has a theme of Kris "Going Nowhere", as if they have no prospects for the future.
Susie is completely obsessed with the present happy life she has with Ralsei, Kris, Noelle, and the other Darkners. She despises her life and is so obsessed with keeping things the way they are that she never wants her friendships to end. Susie also has no past worth caring about.
Ralsei is obsessed with protecting the future and preventing the final tragedy of the prophecy, Ralsei doesn't really have a "past" and neglects his present life. He doesn't decorate his room, he doesn't consider his own likes...
All of these seem like they're gonna be character flaws that are challenged later, though Kris to the greatest extent. Susie and Ralsei's mindsets are significantly less destructive than Kris' obsession with the past.
It's kinda like Sonic 06, Shadow has come to terms with his past, Sonic lives in the moment, and Silver exists to protect the future. Past, present, future.