Shuma is a dimensional ruler. An elder god with his own reality. Able to pretty much do ANYTHING he wills in his reality. In his reality, probably on a par with Aggamotto, who was once able to fight Galactus to a stand still within his own realm.
But, when he comes into our reality, he isn't all he normally is. Still at Elder God level though. VERY powerful.
Korvac, on the other hand, is basically on the same level as a dimensional ruler for his universe. Able to pretty much do ANYTHING he wills in his reality.
Shuma, entering Korvac's universe, would probably put up a great fight, but in the end, Korvac is too much.
It was actually stated that Agamotto couldn't kill Shuma-Gorath, and he was so powerful the Vishanti had to make an agreement not to interfere with him
Gender: Male Location: somewhere within time & space
I haven't seen the respect thread, because honestly Mike,
I never look to respect threads for info,
respect threads can be ... misleading,
sometimes, outright fallacious.
So no, I actually have all of Shuma's appearances instead,
giving me the intricate details to everything Shuma was, and was capable of.