I've always thought that Momiji would be a lot younger than Aya and Hatate too.

Small Momiji is not only cute, but would explain nicely why she is so friendly with Nitori and so cold towards Aya in canon.

Y'know, for youkai that are quite “ageless”, the past surely was a bit more “modern” than I think... I wonder if Aya actually found Momiji on the outside world? Or did Momiji was a bit more younger than Aya?