King of the Concrete Jungle

The world goes boom
Zombie apocalypse + perma-night + mutation apocalypse + superpowers + ratio + whatever-BS-I-can-come-up-with
The MC has the power to manipulate stone, metal, and most things with crystalline molecular structure. What does that mean? Limitations.
He CAN'T rip the iron out of your blood, it's in an organic chemical compound. He CAN turn the concrete under your feet into quicksand and turn the rebar in the walls into snakes, since it's a crystalline molecular structure.
Not for long since in order to turn stone into liquid he needs to break the crystal structure and he quickly loses control over it, resulting in the matter turning back into a crystal structure and solidifying.
The MC is strong but it's only after a couple of years into the apocalypse. He spent the first few years barely scraping by and we meet him right before he gains his ability. Thanks to his newfound power he becomes cocky and overconfident. I do give a few valid reasons for why he's so confident.