Janis

Drop Point: Kaede's village

Janis is from the spin-off game Inuyasha: Secret of the Divine Jewel.
In the CJM-verse, she is Willis's little sister (from Digimon). The blonde knows Inuyasha and the rest from her timeline, though the ones she meets here don't, they will feel something akin to friendship to her.
The blonde is also a reincarnated goddess and she wields a Nagatina in battle.
Lore: Janis will be a resident in to be named Tokyo and will be seen about. She will eventually come into contact with Inuyasha and the crew and join them. With this, the dynamic will change which will bring unwanted drama and new futures.