Shijou Saikyou no Deshi Kenichi, Holyland Recommendations
Both History's Strongest Disciple Kenichi and Holyland center around a downtrodden protagonist who is forced into fights of ever escalating difficulty. Both learn moves from multiple styles and have to conquer their inner fear to fight delinquents, with each fight a consequence of having survived the previous fights.
Of the two, the protagonist Yuu in Holyland is a bit more of a self-made fighter in that he tends to learn his moves from his friends and opponents rather than from an illustrious pool of masters.
In the end Holyland trades in Kenichi's ecchi elements and over the top anime-style martial arts for a more realistic style,