Shūkurō
Tsukishima

Shūkurō Tsukishima is a Fullbringer and the most quietly frightening antagonist in the arc, because his ability does not attack the body at all. Book of the End is a bookmark-shaped blade, and anything it cuts gains him as part of its past. Not a memory implanted after the fact, but a rewritten history: the target remembers years of friendship that never happened and acts on it completely.

He uses it on Ichigo Kurosaki's friends and family while Ichigo is training, so that when Ichigo comes home the people closest to him greet Tsukishima warmly and treat Ichigo as the one behaving strangely. It is an isolation tactic run at leisure, and it works. By the time the deception is visible, Ichigo has lost every source of support he had, which was always the point.

Underneath the calm is a dependency he never examines. Kūgo Ginjō raised and mentored him, and Tsukishima's loyalty to Ginjō is the one thing his ability cannot rewrite because it is genuine. He fights Byakuya Kuchiki and, even bleeding out on the ground, keeps feeding the false past into him. When Ginjō dies, the composure disappears entirely and Tsukishima goes after Ichigo in a rage that has nothing strategic left in it.