Looking for a yaoi/shounen ai manga, but can't remember the name. Please help!

So the basic plot is that there are two male leads. One of them is a gang leader/yakuza/boss of a group and the other is his bodyguard/follower (also the person whose pov it's usually told from). The gang leader also has a female sister, maybe his twin, I forget that is evil/or he just doesn't get along with, but still loves. She's an assassin i think and the other make lead also likes her. The male lead whose pov we usually see also uses a sickle like weapon I believe. At one point he even leaves the gang because another male the boss was involved with appears. This is a yaoi/shounen ai at least 5 years old, but most likely older. I've tried looking through mangago myself, but there's just too much to go through, so I hope someone knows this manga. If it helps this manga also had a spin-off about a guy from the other gang and it was about how people were being monitered constantly everywhere by some company/group and how they had to work to destroy it. That was also either a yaoi/shounen ai manga.