I'm in Marvel, My Sister Is the Ancient One

Traveling through Marvel to become the younger brother of the Sorcerer Supreme, the Ancient One. I originally thought that I was hugging a thick thigh and could row without an oar. However, the system suddenly appeared. "Sign in to get the body of the God of Magic, and your magic abilities will be maxed out instantly!" "Sign in to get the body of thunder spirit and transform into the most powerful lightning king!" "Sign in to get the Infinity Glove, kill everything instantly with no side effects!" "..." Supreme Mage Ancient One: "How about you become the Supreme Mage?" ... This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.