Spoilers for those who have not read JJK manga!

Okay, Sukuna is in Megumi's body - meaning he has access to Shrine and Mahoraga.

Sukuna I'm going to take his statements as literal. Sukuna is constantly in covers stated to have the power to destroy the world.

Now this normally can be taken as referring to society or humanity, and all that, but the distinction is made in the manga. It is still quite far fetched, but for the sake of this fic, we'll have our MC have that power.

I find it fair, since if his durability and strength don't match a viltrumite's then... He's fucked. He gets speed blitzed and then his head is off his shoulders and he's dead. Not really fun now is it?

Besides, personally I like to think the statement is literal.

Also, Sukuna's cleave and dismantle. Dismantle is fixed and can cut Viltrumite's, but cleave, can adapt to the target's durability and cut right through them - though its condition is that it requires physical contact with the target, 

Sukuna also has reverse cursed technique meaning he should logically be able to reverse his Shrine, which is coneptual cutting as he was able to cut through infinity with it, so Sukuna can attach things together.

A limited form of Matter Manipulation basically. Limited by knowledge and range.

Besides all this he has the Ten Shadows as well.

Though Sukuna needs to learn to use his powers - needs to learn domain expansion, his cursed technique etc, so don't expect him to be able to fight Omni-Man or Battle Beast, or even an average Viltrumite till sometime later.

Also, for those who don't know the rest of Sukuna's abilities - he has fire powers, basically he can shoot out a single flame arrow, it's single target, but can burn literal fire itself - he killed a spirit of fire with it.

He can though apply it in a domain expansion so that it is area of effect, but takes a bit of setup.

Ten Shadows are complicated since there are 10 spirits, with each their own abilities.

But the most important is Mahoraga, the one called the Divine General.

He can basically adapt to any phenomenon so long as he survives the first couple attacks, after which he becomes immune, or can even create an attack that negates your abilities.

So yeah, hope this cleared it up. See you all in the chapters.

Bye!