Shuma-Gorath is a quite powerful magic user. But let's see how far he can go in this scenario.
The various mystic entities of the Marvel Universe have decided that Shuma is a nuisance to their goals and a general d!ck, so they plan to kill him. Rather than let Shuma-Gorath get the jump on them elsewhere, they decide to go directly to Shuma's native dimension and give him a taste of his own medicine. Unfortunately for them, Shuma-Gorath has placed a mystic barrier around the realm that will only allow one visitor at a time.
If a challenger loses to Shuma-Gorath, that challenger gets its essence absorbed by Shuma-Gorath before the next challenger arrives. Battle can only be won by the challengers if Shuma-Gorath is destroyed. BFR is not an option since this is Shuma's realm.
How far does Lord Gorath get?
Note: All characters are their 616 versions, no alternate reality versions here.
10) Master Order
13) Galactus (has just consumed a solar system)