Kenichi the Mightiest Disciple 2: Masters Arc

From Shogakukan: Fight, O Fists! Burn, Heart of Justice!! Shirahama Kenichi, once an unremarkable high school student, has grown stronger under the guidance of the absurdly strong and beautiful girl Miu, spending his days training at Ryouzanpaku, where masters of various martial arts gather. Having overcome countless trials and matured, a new enemy now appears before Kenichi a ninja? And even former comrades, as well as the arch-enemy YOMI, re-enter the fray.