Board Thread:Theories and Rumors/@comment-5336393-20190110151206/@comment-30938718-20190125140839

MemoryAngel wrote: The Overlord isn't part of the Wu/Garmadon family.

And Wu remembered the FSM on the Day of the Departed, implying his spirit was in the "Departed" Realm like all the other spirits that were remembered that day. Ray and Maya were alive and Kai and Nya honored them in DotD.