The biggest difference between Hayato and Shinrei is that Shinrei is an isolationist. Most characters do not become isolationist unless they have some sort of history that haunts them and its dark and deep. You will learn how he ended up in the state where he trusts no one later on. I don't want to character develop in the OOC so I will leave you to think about that one.

Tsukiko's character like Shinrei is also haunted by the past, but she isn't an isolationist like Shinrei. She's more of a behavioralist whose attitude can change on the fly at times. She's very difficult to understand because her emotions are difficult to understand. Like one point she can be happy and at another moment you can invoke her wrath, [i]looking at you Vincent![/i] People who think they understand usually end up regretting their assumptions. She is a very complex individual who her brother doesn't even understand. She can be an isolationist herself at times especially if someone has pissed her off or if her real emotions she is trying to hide leak out of her tough exterior. Typical responses at that time are [b]"shut up, don't look"[/b] and [b]"leave me alone!"[/b] When she's in the state of distraught and lost in her own depression she doesn't want anyone else to see her like that. It's why she tries to hide it most of the time. Haas got a dose of it when it almost showed on her when she was around him. He didn't cause, but she did feel grief toward rambling on about something he probably didn't want to listen to.

They do share similar traits personality wise, but still there are unique differences in them which allows to easily distinguish that they do have differences that exploit themselves if you look very deep into them.