Ami

A spirit of a cat in form of a girl. Akari and President Aria meets her in episode 4 of Aria the Animation ("That undeliverable letter") where she tasks Akari with delivering a letter to an address she couldn't locate on her computer. She later shows up in various flashback presentations, like the one in episode 13 of Aria the Animation.

Ami is an anime-only character, and does not show up in the manga.