Thanos was omnipotent, numero uno, he technically would not need any help from the rest of the entities, in the Infinity Gauntlet series... There is nothing that any of the characters in either universe could do that he could not overturn, The living Tribunal said himeself that if he fought Adam Warlock that their battle would destroy all of creation, and asked if he wanted this... Warlock said no, so let me point something out. It has never been determined whether or not The Tribunal was more powerful than the gems, also it was Adam Warlock that allowed for the gems to be unable to work in unison... once he allowed this the Tribunal then made it a law... not the other way around. As far as I'm concerned Adam Warlock with the gems may have been able to overturn the Tribunal as the universes most powerful avatar. If someone can prove me wrong please show me with scans, otherwise read the Infinity Watch comics. You may come to the conclusion that I have.