- Aquarius: "The Water Bearer" is a long-haired mermaid that can only be summoned into a body of water. She is selfish and taunts Lucy, often attacking both Lucy and Lucy's enemies with a torrent of water. Her occasional "off-days" would most likely be spent on a date with her boyfriend, Scorpio.
- Taurus: "The Golden Bull" is a minotaur with a white and black splotched coat and a nose ring. He wields a giant two-bladed axe. He is a pervert and constantly compliments Lucy's body.
- Cancer: "The Great Crab" is a hair stylist with crab-claw shaped hair. He has six large crab-legs that come out of his back and carries around scissors. When he is first summoned,Happy assumes that Cancer would end all of his sentences with kani (crab), but in reality, Cancer ends all of his sentences with ebi (shrimp).
- Virgo: "The Maiden" is a maid with shackles and chains around her wrists. Her ability is to tunnel underground. Her appearance reflects her current master's preference: when introduced under the ownership of Duke Everlue she looks giant and overweight, but she slims down after Lucy takes possession of her key.
- Sagittarius: "The Archer" is a man wearing a horse costume that uses a bow and arrow. It is given to Lucy as a reward for saving Galuna Island. He ends his sentences with "moshi-moshi" (hello-hello).
- Leo: "The Lion" is Loke, who gives his key to Lucy after she helps him return to the spirit world. He was previously owned by Karen Lilica, whose abusive attitude towards Aries resulted in an argument where Leo refused to return to the spirit world until she released him and Aries from their contracts. By doing this, Leo prevented Karen from summoning other Celestial Spirits which caused her death on a mission. After he regains his former powers as a Celestial Spirit, Loke demonstrates that he is much stronger than he used to be when he was a member of Fairy Tail. Leo is able to appear into the real world at will without being called; he can sense when Lucy is in danger, and come assist her when needed.
- Scorpio: "The Scorpion" is a man with a cannon in the shape of a mechanical stinger, and hair split into two different colors. He is Aquarius' boyfriend.
- Gemini: "The Twins" are two small imp-like creatures who can copy others in terms of appearances, abilities, and even thoughts. They were previously owned by Angel.
- Aries: "The Ram" is a young girl dressed in a woolen dress and long boots. Aries's past masters treated her badly and hardly ever took her feelings into consideration; when Karen was killed by Angel, Aries fell into Angel's possession until Angel is defeated by Lucy.
- Capricorn: "The Goat" is a tall man with a goat's body. He was originally Lucy's mother's spirit but she fell ill and passed her keys on to three other mages. Among these was Zoldeo, who held Capricorn's key. However, Zoldeo became swallowed by darkness and committed a taboo by using Human Subordination magic on Capricorn, which fused their bodies together.
=== Silver Keys===
- Crux: "The Southern Cross" is a large humanoid stone-made cross with a cross-shaped nose and mustache. He specializes in searching for information on different spirits and their masters.
- Horologium: "The Time Piece" is a living grandfather clock that is large enough for people to hide in. Lucy usually does this for shelter or as a mode of transportation. Once inside, Horologium speaks for her, ending every sentence with "my Mistress says".
- Lyra: "The Lyre" wears a bonnet, a dress, has wings on her back and carries a harp. She sings about emotions and often likes to take requests.
- Nikora the Canis Minor: "Nikora", named "Plue" by Lucy, resembles the same Plue from Hiro Mashima's previous work, Rave Master. He has no special abilities or powers, and serves more as a pet for Lucy.