Sagittarius

Sagittarius is an Archer Celestial Spirit who wears a horse costume that is currently owned by Lucy Heartfilia.

Appearance
Sagittarius, despite how people would view him, is a tall, black-haired lanky man wearing a horse costume. He has rustic, almost medieval clothing. His weapon is a bow and he has a giant quiver on his back.

Galuna Arc
After saving Galuna from the Shadow Drip, Lucy receives Sagittarius as a reward. At first Happy tries to take the key to sell but Lucy keeps it. Gray and Natsu tries to imagine how Sagittarius would look like. Gray thought Sagittarius' appearances is a Horse with a human body. Lucy Says he's like a centaur. Natsu on the other hand thinks he looks like a strange flower with octopus legs.

Phantom Lord Arc
Lucy Summons Sagittarius during Natsu's fight against Gajeel. Much to Lucy's surprise, Sagittarius resembles Gray's description. Lucy commands Sagittarius to try and make fire for Natsu to eat so the battle will be even but Sagittarius says that he can't. Soon, however, Sagittarius figures out that Lucy wanted him to find a way to obtain fire. He shoots some nearby machinery and sets it a flame for Natsu to eat.

Fighting Festival Arc
Lucy summons Sagittarius during the fight against Bixlow. He shot down all Bixlow's dolls, but he is soon defeated, because it turns out, that Bixlow has a spare set of them.

Oracion Seis Arc
Lucy Summons Sagittarius again to stop "Gray" from attacking Natsu. However "Gray" attacks Lucy who is protected by Hibiki. Hibiki say that "Gray" isn't the real Gray but Gemini. Gemini takes advantage of Hibiki's weakness of women by transforming into Lucy and removing her top, shocking Lucy, Hibiki, and Sagittarius. Gemini commands Sagittarius to attack Hibiki and Sagittarius does so. Lucy force closes him but Gemini summons him. Lucy tries to force close again but since Gemini summoned him she can't force his gate closed. Angel walks in and tells Gemini to stop and Gemini reverts to their original form, forcibly closing Sagittarius' gate.

Magic and Abilities
Archery: Sagittarius' weapon of choice is a bow and arrow, he was able to easily crush Bixlow's toys with his arrows, going right through the dolls without stopping. He also seems to be very resourceful as he was able to create fire by shooting electrical equipment so Natsu could replenish himself.

Trivia

 * Sagittarius seems to say "hello hello" before anything he says.
 * In the english version, however, it retained the original "Moshi Moshi" greeting from the japanese version.
 * Much to Lucy's surprise, Sagittarius actually looks more like Gray's assumption than what Lucy thought before either of them saw what Sagittarius looks like.
 * Actually, Sagitarius form is a resemblance of both Lucy and Gray opinion. Gray said: Uma.. err.. Horse Upper with Human body, Lucy said Human upper with Horse body.
 * Sagittarius is the only zodiac key Lucy obtained during the series, that didn't leave its former summoner and ask to form a contract with Lucy.
 * When Natsu thinks about Sagittarius' appearance, the flower creature resembles Nakajima from Mashima's last work Rave Master
 * The idea of a horse hat may have come from the cover number 122 of Rave Master, where Plue is using it.
 * Sagittarius also likes to salute people.