Xcution came together for a shared purpose and worked together to erase their Fullbring powers. Tsukishima discovered a way to transfer their Fullbring powers to a Substitute Soul Reaper. After the Substitute Shinigami Soul Reaper accepted the powers of several of our group members. Tsukishima suddenly had a change of heart. He killed both the Substitute Soul Reaper and the members of our group who gave him their powers, and disappeared from the Xcution.
He’s aim is to prevent the current Xcution Leader Kugo Ginjo and all other members. His aim would be to make contact with Ichigo Kurosaki, a Substitute Soul Reaper. He attacked Uryu Ishida and made contact with Orihime Inoue, and tried to attract your attention by using a different, and more violent means than the current Xcution did.
Spoiler: What had been explained above was from Bleach 350, after a few episodes, you’ll find out that this technically wasn’t correct and there’s a larger story to all this.
Don’t forget to watch next week’s Bleach 351 episode! It’s going to be amazing!