It's actually based on canon. Though Kogasa mainly refers to herself as the standard "watashi", in Sanae B after Sanae suggests Kogasa is behind on things, Kogasa catches the implication saying "What, you mean I'm behind the times?" while using "わちき"/wachiki for I. なんと、わちきが時代遅れともうすか
It's guaranteed she'll utter "wachiki" Very obscure, untranslatable reference: "wachiki" is an archaic first-person pronoun that was used by geisha and prostitutes in pre-Meiji Edo. What makes Sanae so sure Kogasa is going to say this, though, I don't know.Umbrella
DreamerOnly eccentric color choices.The unseemly "odd-eye".