This Quirk gives Ken the ability to manipulate cement-based material simply by being in contact with the surface.
With Cement, Ken can create all sorts of structures for others to use, such as Gym Gamma and the arena used for the fighting portion of the U.A. Sports Festival. Because of the nature of this Quirk, Ken has a large combat advantage on urban areas because of the abundance of concrete.
Inversely, he holds little combat ability on settings where concrete is rare or nonexistent, such as in the countryside.
In the anime, Ken' hands appear to glow in a faint green light whenever he's using his Quirk.
- Cement - Wikipedia article about the substance found in objects Ken can manipulate.