Anyone pls tell me what manhwa title in the last page?

I think it’s just this one! J has white so that’s why he looks different

It's probably a promo picture from what's still to come from this manhwa.

As the others have said, it is from this series but we haven’t seen the stuff that leads to it yet

That's actually his hair colour now, like Kaneki. He just dyes it after he came back from the rift.