- Ambiguously Bi: Juli. Before leaving for seminary, Juli tells Erich that around him, all his good memories return. Among those memories? The first girl he liked.
- Moment of Awesome: Admit it, you cheered when Erich told off Juli's grandmother for making snide, racist remarks about her own grandson.
- Periphery Demographic: Initially serialized in a shoujo magazine for elementary school girls, the story's complex and sophisticated themes drew in an unexpected audience, including young men and others who otherwise would never have picked up a shoujo magazine. The popularity of Thomas helped create the modern Periphery Demographic for shoujo comics at large.
- Rape as Backstory: Siegfried and his friends may have done more than just torture poor Juli...Juli: (to Erich) [Siegfried] and his friends used me as they pleased [...] I had no say in it at all.
- Values Dissonance: Juli's view of his abuse at Siegfried's hands as a "sin" for which he must atone can be jarring to modern readers. Possibly counts as Deliberate Values Dissonance, since this attitude isn't unrealistic for a student at a conservative, 1970's-era boarding school.
YMMV / The Heart of Thomas