SQUADRON SINISTER Villain Team entry

[Monolith]

The Squadron Sinister appeared first as foes of the Avengers, evil counterparts of the Squadron Supreme from another dimension before we even met the heroes! These Sinister foes were natives of Earth-616, but ultimately disbanded as the members were too unruly to work together. A new version of the group reformed years later, also calling itself Supreme Power, as adversaries of the Thunderbolts. They are a complicated mix of legacy villains and heroic doppelgangers.

https://mightyavengers.net/groups/squadron-sinister