Capricorn is a tall humanoid, towering over most average-sized Celestial Spirits, who possesses many goat-like traits: his body is covered in short, brownish white fur, with longer tufts covering his lower face, resembling a goatee, and the back of his legs, which greatly resemble those of a goat, being slightly bent backwards and ending in dark hooves. He has short, thin ears sitting on top of his head, with a distinctive, elongated oval form, and horns which curve downwards and jut frontwards framing his face. From his lower back sprouts a mildly long tail ending in a dark tuft of fur, and his fingers sport long and dark nails (initially portrayed as light in color), highly reminiscent of claws. His elongated face possesses marked cheekbones and a prominent, large nose; his eyes are always hidden away by a pair of black, mirror polished shades, which were initially portrayed as having distinct, separated lenses, with an elongated oval form, but were later given a more compact appearance, with the lenses fusing into a single one, possessing a hollowed part in order for them to rest on Capricorn’s nose. The shades, predictably, come with dark arms, which, however, aren’t shown resting anywhere, due to the Mage’s ears being elsewhere. Capricorn possesses prominent, toned abdominal, and, while initially portrayed as lean-built, was later given a more massive, muscular appearance. For attire, Capricorn wears a formal twin-tail butler suit that covers his arms and legs in his contract with Lucy Heartfilia.
Capricorn is shown to be quite loyal to 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". He also seems to appreciate the idea that Magic is based on love, as he compliments Lucy's interpretation of "The One Magic." In addition, Capricorn is highly skilled in teaching others about Magic, as Lucy summoned him so that he could instruct her on how to raise her Magic Power level.
Expert Hand-to-Hand Combatant: Capricorn has demonstrated great physical prowess, as he is both exceptionally fast and strong. He was able to elbow Hades in the face with relative ease. He can also deal series of precise punches with ease.
Enhanced Strength: Capricorn has demonstrated a good amount of physical strength, demonstrated by the fact that he was able to carry his owner, Lucy, in one arm and carry Natsu Dragneel in the other at the same time from Grimoire Heart Airship to Fairy Tail's campsite on Tenrou Island.
Immortality: As a Celestial Spirit, Capricorn cannot die, unless he is somehow forced to stay in the Human World.