Infinite actually has more depth to him, as a character, than I think a lot of people realize. Not that he's a particularly deep character, but there's more to him than just being new, arrogant villain #300.
You see, his power set is the ability to create illusions. It's just that the brain is so convinced that those illusions are real, that the body reacts as if they were. However, this is to coincide with the fact that Infinite's strength, that he loves to talk up, is also an illusion. His key motivation is proving that he's not weak, as Shadow's mean words kinda hit him a little too hard. To prove Shadow wrong, he becomes part of Eggman's Phantom Ruby project, donning a mask and taking the name of Infinite. However, that mask and identity are just a facade to cover up his own insecurities. Despite his insistence that he's strong, and the heroes are weak, none of his strength is his own. It's the ruby's. His strength is entirely fake, based on a cover-up identity to hide his own weakness. The strength of the guy who creates illusions is an illusion in of itself. Deep down, he's still the same insecure faggot he was after Shadow kicked his ass.
I feel like I spent too many words to explain something fairly simple.