Karyu is Zane's Son from the Future.
Chapter 21 soft-confirms Karyu has come from the future and the only thing we know about his parentage is that he's Balta's son and the only things we know about Balta is that Balta is a woman and is good at infiltration. My theory is that Batla infiltrated the Cyber Style School and from there very much did with Zane. Chazz will be Reforged into a Minion or become Brainwashed and Crazy
...and he'll try to either try to kill Karyu or try to force Alexis into loving him. Rain won't become Yugami's officially lover...
... Zael will.