Board Thread:Theories and Rumors/@comment-43984378-20191202112454/@comment-43984378-20191205214031

Another reason why I think he's the Overlord:

Garmadon villlany gap: 2012~2018=6 years

Overlord villany gap(if Unagami=Overlord):2014~2019=5 years

Since they were very similar anyway, maybe their gap is similar, too.