Daiakuji (v2.18.0) by AliceSoft

Sometime later, Yamamoto Akuji, scion of the Wakame Group, the most powerful organization in the city of Osaka, returns home after spending years as a prisoner of war.
He is greeted by an unfamiliar man, who informs him that his family’s business is now under the control of Ichihashi Ran, his grandfather’s former mistress, and that he is no longer welcomed within its walls.
Before he has any time to argue, Akuji is swarmed by his former subordinates and, weakened by his time in captivity, beaten unconscious and left for dead.
Upon regaining his senses, he finds himself in the custody of the Youth Service Group, a small community patrol squad created in the fallout of the Wakame Group’s waning power.
Recognizing an opportunity, Akuji assaults his captors and forces their leader, Aoba Youko, to submit to his will.
With a foothold now established for himself, Akuji sets his sights on amassing enough power to reclaim his birthright…
...and he’ll do whatever it takes to get it done.
The battle for Osaka has only just begun!