After absorbing the mutant core, Akira gained Kitsune traits like Reia and had the same abilities. However, due to the nature of his essence, everything he touched that was mutant-related would rot away. With every step, the corruption would eat the slime floor and prevent it from regenerating.
This made him anti-mutant, a perfect counter to them as he was untouchable, but there was a limit and that was his essence. Although he may be able to dispose of mutants quickly, his own limited supply would eventually run out. Especially corrupted as one of the drawbacks was that it consumed a lot of essence when used since it was more complex than basic essence like fire.
It was also the main reason why he resorts to his lightning as it is much cheaper to use than his corruption.
