Its been 12 years since Darkness died. Missy isn't cheerful anymore. She's actually sadistic and depressed.
Shadow and Jeff are happy with their family but without Darkness there wouldnt have been a family there in the first place.
Slenderman only cries in his room, away from the others.
Hoodie hasnt been seen for years. The only evidence he is alive is the presents he sends to Darkness and Shadows kids.
As for Liu...he is trying his best. Having kids is hard. Everyone thinks he is insane since he still believes Darkness is alive out there. He knows though. He knows she is alive. He needs to find her.
To properly wed her.
Whoever killed her will die.