Karate Shoukoushi Kohinata Minoru - Vol. 2 Ch. 18 - Bloody Makiwara Special Training

[MangaDex]

 

[lionfromnorth]

That's the spirit!

 

[Kaarme]

Once his fists heal, the normal human skin will be replaced with proper elephant skin for martial artists.

 

[Tibanderstap]

The best way to get stronger is to break every bone in your hand apparently