Shijou Saikyou no Deshi Ken`ichi  

History`s Strongest Disciple Kenichi, HSD Kenichi, HSDK, Ken`ichi, Kenichi, el Discípulo Más Fuerte de la Historia., Kenichi, o discípulo mais forte da História, Kenichi: The Mightiest Disciple

Kenichi Shirahama is a student who prefers reading self-improvement books over physical activity. Despite his initial reluctance to join the school's karate club, he eventually does so after gaining the courage to become stronger. However, when he joins the club, he is forced to fight an upperclassman who wants him kicked out. Kenichi nearly gives up until he meets Miu Furinji, a mysterious classmate at his school. To prepare for their upcoming challenge, Kenichi undergoes rigorous training at Ryouzanpaku, where he learns various martial arts from the dojo's masters. With this newfound strength, Kenichi defeats his upperclassman opponent and gains the attention of a powerful gang known as Ragnarok. Determined to protect what he loves and face increasing adversity, Kenichi decides to combine all the martial arts he has learned into one unique fighting style.