UQ HOLDER! Vol. 15 (Kodansha, 2018)

After travelling all the way to Kyoto, Tota and Kirië finally track down Nagi's old workshop, where they meet Albert Chamomile, Negi Springfield's old partner. There, Albert shows Tota memories from Negi's past, including an alternate timeline of how Negi's life would have been if Tota didn't exist. Tota watches from the sidelines as a decisive battle unfolds between Negi and Nagi, and finally sees firsthand the overwhelming power of the two mages that came before him.