七つの大罪 · Nanatsu no Taizai
Nanatsu no Taizai · convention
A Christian catalogue of vices, imported into manga as a naming scheme for seven-member teams.
Filed by its count, not its title
Reduced as a phrase, “The Seven Deadly Sins” would sit on The Telling — but that would be reducing wording this reference chose. The set is filed under 7 · The Inquiry instead, because 7 is what its author chose, and a chosen number outranks an imposed one.
Pride, greed, lust, envy, gluttony, wrath and sloth — a mediaeval Christian taxonomy of vice, adopted in manga as a ready-made set of seven names with built-in personalities.
Very little on its own; the value is entirely in the labels. This is the opposite of a taxonomy that carries rules. Nothing about the seven sins constrains what a character can do, and the set imposes no ranking, so an author who adopts it gets seven distinct silhouettes and no obligations.
That cheapness is why it recurs. A borrowed set with strong names and weak rules is the most economical thing an author can pick up.
Western religious material enters Japanese popular fiction largely stripped of doctrine and kept for its imagery — crosses, angel ranks, the sins. This reference notes it without complaint: it is the same operation manga performs on Chinese divination in the Eight Gates, and Western fiction has been doing it to Japanese material for just as long.