Nagato Tohsaka
Around the 1790s, Nagato headed the Tohsaka family, who had quietly practiced Christianity for generations despite the official ban. Everything changed when a mysterious old man showed up and introduced them to sorcery instead.
Nagato's real education came later, when he ran into Kischur Zelretch Schweinorg during his travels. After covering Zelretch's hotel bill—a small gesture that apparently went a long way—Zelretch agreed to teach him magecraft in return. Technically Nagato became his pupil, though Zelretch never took it too seriously; he mostly just checked in on Nagato whenever he felt like it, treating him more as someone to look after casually than a formal student.
Content compiled by AnimeList.moe from publicly available sources.