Viperfist

Tangguh was always bullied by the bullies at his school because he was weak and easy to bully. Even so, Tangguh still has a good heart and one day if he can become stronger, he is determined to protect the weak.

Unexpectedly, a new student named Arang turns out to have martial arts knowledge and protects Tangguh, so Tangguh asks Arang to meet with his teacher so he can teach him.

(Source: Google Play Books, translated)