Ryoshu isn't going to help Gubosang because the problem with Gubosang was never the teamkilling. Teamkilling work's just fine. The problem is that his S1, S2 and counter are unfettered dogshit that deals no damage. His S3 requires a bunch of turns before you can use it as an actual team killing skill and even then it's just a worse version of the EGO.

The fundamental problem with the ID is that you're better off using a Yi Sang ID with actually good skills and the Fell Bullet EGO instead of the FB ID.