Hardening

Hardening is a Quirk used by Eijirou Kirishima.

Description
Eijirou's Quirk gives him the power to harden any part of his body. The ability not only protects him from physical attacks, but also from heat and shock waves. This Quirk is strong enough to protect Eijirou from several tons of metal falling on him as well as several explosions caused by Katsuki through an extended amount of time. It can be used as both the strongest defense and the strongest attack.

The drawback to the Quirk is that there is a limit to how much damage the hardened skin can withstand, causing the hardening to slowly dissipate.

Trivia

 * This Quirk is very similar to Steel, and the two appear to be roughly equal in terms of power and effectiveness.