Flint

Flint (voiced by Coy Stewart and James Mathis III) is a Marvel Comics character that appears in Avengers Assemble.

He is a teenager who was exposed to Terragenesis, turning him into an Inhuman with the power to control earth, rock, and stone. He was caught in the crossfire of the Inhuman Registration Act, and was later mind-controlled by Ultron, until he was freed from his control by the Avengers.