All you gotta know is that Hirata is the main antagonist trying to kill Yashiro so he can take his place as the head of the group or something. All these Japanese names make it confusing to tell what is going on.
Misumi, is a big shot part of Doushinkai (a big Yakuza group) Hirata and Yashiro are leader and second of Shinsekai (a group under Doushinkai) .
Nakamoto (the ugly dude that was shot by Hirata) is part of Gouda group (a group under Sanwakai, another big Yakuza group). Hirata thought the Gouda group would join the Sanwakai, so he tried to kill Yashiro and cut ties with the group so he could join the other. But turn out it won't happen, so he blame the murder of Nakamoto on Yashiro.
Sugimoto is Yashiro underling, like Nanahara. He was shot at the end of this chapter.
dude re-read it and I promise the plot will blow your mind cause its that good
Here's a run down, excuse the poor spelling and quick description:
Top group - Doushinkai group (Misumi is a board member) (Amou is his step son from a short marriage with a previous mistress). (Misumi's right hand man was killed by Hirata)
Sub group- Shinseikai group (was previously headed by Misumi, but he made Yashiro his "son" and boss of this group). (Nanahara is Yashiro's right hand man) (Sugimoto is Yashiro's underling) (Doumeki is Yashiro's bodyguard and driver).
Sub group- Matsubara group (Ryuzaki is the head of this group, and also exchanged sake with Yashiro making them group brothers. Ryuzaki knew Yashiro when he was 19 and being used as a group tart for his men)
Sub group- Chokuseikai (headed by Hirata who wants to be higher up with the Doushinkai group, so he is annoyed that Misumi made Yashiro his "son" and gave him the position of boss seeing) (Hirata killed Misumi's right hand man in order to get a higher up position, and now he is trying to kill Yashiro)
There are a few new characters or those associated with Hirata who I can't remember their names that have been introduced in the latest chapter.
Go read analymous post. It will help you!
http://www.mangago.zone/home/mangatopic/3057967/
At this point, I'm just reading the manga blindly cuz I don't understand what the hell they're talking about, lol. Sanwakai, Doushinkai, Gouda group, Hirata and ugly dudes who I don't give a shit about and what are these things again? Most of them look the same so I can't differentiate the characters. And who the hell is Nakamoto and Sugimoto again? There's also the mention of exchanging sake cups so many times lmao. Now while the characters are having bloodshed and dispute over drugs and betrays whatsoever, I only cared about Doumeki and Yashiro lol.