Milky

Milky is a pale blue Chihuahua with pink inner ears and fluff. She has green Jewel Eyes. She wears a light green bow around her neck and a light green frilly cap on her head.

In Jewelpet, Milky appears to Keigo's potential bride Chie when Diana curses her into becoming a delinquent based on her repressed feelings. In later episodes, she becomes a worker at the Strawberry Café along with Peridot and Luna.

In Jewelpet Twinkle, she's one of Halite's Jewelpets, again with Luna and possibly Peridot. In one episode, all three travel to the human world with Akari. She and Luna later become commentators for the Jewel Star Grand Prix.

In Jewelpet Kira Deco, she's a sweet potato seller who makes prophecies about the end of the world.

In Jewelpet Happiness, she takes care of a large dragon who's suspected of causing havoc on campus. She defends him.

She's in the background in the other seasons.

(Source: Jewelpet Wikia)