Capricorn

Capricorn the Goat aka Caprico, is a Celestial Spirit that was possessed by Zoldeo, one of the Seven Kin of Purgatory, and was thus his body was part of Grimoire Heart. When his body was part of Grimoire Heart, it had authority over underlings such as Yomazu and Kawazu. Since his freedom from Zoldeo, he has left Grimoire Heart for the Fairy Tail Guild with his rightful summoner Lucy.

Appearance
Caprico is a tall and thin goat-like humanoid. His goatlike features include floppy ears, curved horns, hooved feet, a prominent nose, a tail, a goatee, and fur lining his legs. He wears a tuxedo-like uniform that only covers the top half of his torso, exposing his prominent abdominal muscles. He wears dark pants with a white design that are held up by a belt. He has a metal bracelet around each arm near the wrist and possesses long fingernails. Lastly, he wears a pair of sinister-looking black shades that prevent others from seeing his eyes.

In the past, when he was contracted with Layla, he wore a more formal attire that covered his entire body.

Personality
Caprico (while possessed) has a calm, serious demeanor and shows little emotion, just like several of his fellow guild members. However, just like Azuma, Meredy, and Rustyrose, he does not maintain his emotionless demeanor for long; when he (Zoldeo) realizes that Lucy Heartfilia is Layla's daughter, he enters a frothing rage. He also looks forward to battling Fairy Tail mages, whom he says should not be underestimated.

After being freed from Zoldeo, Caprico shows to be quite loyal of both Layla and Lucy claiming that he "cannot give his power to Lucy as it already belongs to her". He is also very respectful as he calls everybody with the honorific "-sama".

History
It is known he was a Celestial Spirit who had a contract with Layla Heartfilia and some relation with Loke during the time. Layla eventually decided to retire from her life as a mage, and her spirits including Capricorn, Cancer, and Aquarius ended with different masters, but he promised Layla that if Lucy decides to became a mage, he would aid her. During this time he was owned and possessed by Zoldeo, a member of Grimoire Heart and became a member of the Seven Kin of Purgatory.

S-Class Trial arc
He is first seen in Grimoire Heart's flying ship, saying not to underestimate the Fairy Tail Guild and that he was born for this day. He is later revealed to be the boss of Yomazu and Kawazu. As the airship draws closer to Tenrou island, Caprico mentions that he will take the upcoming battle seriously. He then looks on as an enormous Makarov intercepts the airship in the bay of Tenrou Island. After Makarov does battle with the airship for a while, Hades tells Caprico to take everyone on board to the island, saying that he would personally take care of Makarov. Caprico complies, using his magic to 'store' away all his guild members before flying out of the airship on his jetpack. As he flies over Tenrou Island, he releases numerous bubbles that contain the Grimoire Heart members. The members then land all over the island, ready to battle Fairy Tail members.

As Lucy's group (herself, Cana Alberona, Loke, and Gray Fullbuster) begin dispatching the lesser-rank members, Caprico appears and transports them away with his magic, saying they didn't have the strength necessary to defeat them and that he alone would suffice. Lucy and Loke show surprise at him being a goat. Utilizing great speed and powerful kicks, he quickly launched several powerful blows on all four of his opponents, knocking out Lucy and Cana and managing to hit both Gray and Loke with another kick, gaining the upper hand. As Cana and Lucy get back up, he explains to the four mages what Grimoire Heart plans to do with Zeref: to create a world where non-magic users cannot survive. Loke explains that his brand of lost magic is Human Subordination, which dampens the magic and fighting prowess of those around him.

Loke tells the others that their opponent is indeed Capicorn, a Golden Key Celestial Spirit, and that since he himself is not human, Loke can fight him on even footing. Lucy is especially unwilling to leave him, but eventually does so after the others persuade her to. As soon as the three depart, Loke powers up his fist with light and punches Caprico, knocking him backwards. Caprico immediately responds by kneeing Loke in the stomach and then summoning a human named San Jao Shin, who slashes Loke with a polearm weapon. Caprico says that he is has no master, and then ponders aloud about Loke's master. He then realizes that the blonde girl that Loke hastily sent away is the daughter of Layla Heartfilia and goes berserk, bellowing that he will not let Lucy get away in one piece.

However, it is then revealed to Leo that Caprico has been possessed by a human spirit. After Zoldeo tried to take over Leo's body, he took a hit from regulus and Leo transfered over his main magic to Capricorn. Originally being left for death by Zoldeo, but Capricorn used Regulus to injure Loke and free him before Zoldeo took control. With Zoldeo's defeat Capricorn was free from his long enslavement and he decides to return to the spirit world to rest and regain his strength before coming back to aid Lucy. His key seems to have been transferred to Lucy, and Lucy senses Loke's victory and a new ally.

Magic and Abilities
Because Capricorn had been possessed by Zoldeo, it is uncertain what Capricorn's true abilities are, given that some of the magic he used were actually abilities belonging to Zoldeo.

Caster Magic User: While possessed by one of the Seven Kin of Purgatory, Caprico was one of the strongest mages to date. He used a Lost Magic called Human Subordination, which allowed him to keep the upper hand in a battle against four of Fairy Tail's mages. He was also able to use Regulus when Zoldeo transfered bodies to Loke.

Master Hand to Hand Combatant: Caprico has demonstrated great physical prowess, as he is both exceptionally fast and strong. Mostly using kick-based attacks such as high kicks, spinning kicks, and knee attacks, he is capable of easily pummeling four opponents onto the ground before they could even cast their spells since he can weaken their power and magical abilities.

Weapons/Items
Jetpack: Caprico used a jetpack for flying that also greatly boosted his speed. This jetpack was used in conjunction with his human summoning magic to efficiently paradrop his allies onto the battlefield of Tenrou Island. However, he seems to have taken it off after he landed.

Trivia

 * Rather than referring to himself with the Japanese Watashi (私 わたし), Caprico refers himself as Mee (私 メエ). This may be referring to how a goat sounds in Japanese standards.