Velvet nodded. She had a suspicion it was more than just the mediation
exercises that were helping Edward. No one knew for sure what Yatsuhashi
had done with his Semblance when he’d tried to heal Edward’s mind …
even Yatsuhashi wasn’t sure. His ability was to erase memories, but it was
possible that there was more to Yatsu’s Semblance than that. It was
something Glynda had emphasized in their second-year classes at Beacon:
Semblances can grow as people do. It was reasonable to assume that he
might have been able to nudge Edward’s mind enough to give him better
recall and help reverse his degenerative mental disease. But Yatsu had
always focused more on controlling his power than testing its limits and
seeing what else he could do. He hated messing with people’s minds.


After the Fall, p. 108