Sometimes I wonder if another new hero group would form under Saitama. Not likely but if it did it would most likely be him, Genos, Maybe Bang and Bomb, Flashy Flash, Sonic, Fubuki and monster Sweet mask.
I think an informal hero group is forming, made up of either people who know/trust Saitama personally or who know/trust those people.
On account of Saitama, Zombieman will not be leaving. On account of King, who is sticking to Saitama for safety, Atomic Samurai and his disciples won’t be leaving. On account of Fubuki, Tatsumaki won’t be leaving.
As to Sweet Mask, he can co-exist with the monster within like you or I can co-exist with cancer. Either he can put it into remission and fully reclaim his humanity or it will eventually consume him. We’ll have to see. It would be good to see that there’s a way back for someone not entirely gone.
Eventually, Saitama will be the king under the hill, able to call on the one group of heroes who can deal with the enemies of civilized mankind. No bets on his knowing that he has that power. :D
