I still don't get what is the 3rd user's quirk

he's able to sense danger like spider man I think

no, thats the 4th one, he is talking about the new one from last chapter, and i dont undertend it too

Oh sorry

here's a better definition

Third User
He has the Quirk Fa Jin, which allows the user to build up kinetic energy before releasing it in a burst to give a boost in speed of power. Deku first used Fa Jin when fighting against Lady Nagant despite having little understanding from its owner, combining it with En's Smokescreen to outsmart Lady Nagant.

Here's a better definition

Third User
He has the Quirk Fa Jin, which allows the user to build up kinetic energy before releasing it in a burst to give a boost in speed of power. Deku first used Fa Jin when fighting against Lady Nagant despite having little understanding from its owner, combining it with En's Smokescreen to outsmart Lady Nagant.

(ﾉ*0*)ﾉ