Atum is immensely powerful; he is believed to be more powerful than any other known god on Earth. Atum emanates light and heat as bright as the sun as blasts and while flying.
Atum possesses god-like abilities, the full extent remains to be revealed. He can generate light, heat, and plasma on levels par with Earth's sun, and can survive even in the heart of the sun or in deep space. He can fly at faster-than-light speeds.
Atum is able to absorb the essences, powers, and abilities of others, even other gods and abstract entities. When doing so, Atum undergoes a physical transformation into Demogorge, with wings, grey skin, and increased power. As Demogorge casts off excess power gained in this manner, he gradually transforms back into his original form.
is atum capable of absorbing beings like galactus?
he's above elder gods who are big time bad chthon got his own dimension he's more powerful then mephesto, dormammu im guessing since he has been sealed out of this dimension, and set one alternate version thor or odin came to the 616 saying that set had taken over the universe including asgard.
Atum the God-Eater/ Demogorge will smite them like he did before, the old elder gods devolve into demons and left into pocket universe to escape Atum wraths including Set, Cthon, Cyttorak etc. Demogorge form is unbeatable it will aborb beings to make it more powerful than before, he can absorb all of the sky fathers on earth and kick Dormmonu, Mepshisto ass out of their own realm.
If Atum faced RKT. It would be a hard pressed fight.. but the Atum would have the Odinforce flowing through him.. and the rune magic? Jesus... Atum at that level would cripple just about every team on earth.. Dr. Strange would have to open a portal to toss Atum on Planet Hulk or something.
__________________ Quotes from Hia8:
"I claimed that the science is sometimes faulty."
"You don't understand. This is fiction. That means none of this stuff really happened."
"There is no writer to purposely ignore a character's natural ability just because it suits the story."
"in some cases because the writer knows that Character A will dominate Character B easily and refuses to allow this to happen for the sake of the story."