Fa Jin

Fa Jin is the Quirk used by the third One For All user and later inherited by Izuku Midoriya.

Description
This Quirk allows the user to build up kinetic energy and use that energy to release an explosive burst of speed and power.

Usage
Deku uses this Quirk while fighting Lady Nagant. He uses Smokescreen to hinder her vision so he can jump around from building to building, gathering kinetic energy before jumping out of a skyscraper and grabbing her.

Trivia

 * Fa Jin is one of the oldest known Quirks in the series along with One For All, All For One, Life Force, Spearlike Bones and the unnamed luminescence Quirk.