Eris Caligo

Eris Caligo is the sister of Idris Caligo and a minor character in the Einstein isekai franchise.

Idris Caligo
Eris and Idris have always been very close to each other, overall closer than they are to their parents. Even after they both move out of their childhood home, with Eris getting married and starting her own business, and Idris starting to train as a knight, they still regularly write letters to keep in touch with one another. Eris tends to worry about her baby brother, fearing that he might get hurt or into trouble, but not wanting to stand in the way of his chosen career path either.