Caelum

Caelum, "The Chisel" (カエルム Kaerumu) is a Silver Key Celestial Spirit that can transform between three forms for its master. It's key was owned by Angel during the Oración Seis arc.

Appearance
Caelum, at its default form, is shaped like a sphere with a halo-like circle at top. It is made of metal and has lines tracing around its shape. The center of Caelum's default body is in a darker shade of gray than the rest of its body and there is a small white circle with a smaller light green circle inside, giving it the appearance of an eye. Caelum can expand its body so that it takes on different forms (sword, flight and cannon are so far the only known forms), but the main circle from its default body remains.

During the time with Katja, Caelum had small changes it's "eye" appeared smaller in comparison. The lines crossing the darker shade of grey on caelum's center are gone.

Oración Seis arc
Caelum is summoned to do battle against Lucy Heartfilia. As it is summoned, it fires a blast at Aries and Loke despite Aries being on its side. Gemini then uses Caelum in sword form to attack Lucy but when Gemini refuses to hurt Lucy because Gemini realized Lucy's love for her Celestial Spirits, Angel takes Caelum to attack Lucy herself, however she misses her shot against Lucy.

Key of the Starry Sky arc
Note: Events in this arc occur only in the anime and do not constitute canon material.

Forms
Sword Form: In this form, Caelum transform into his namesake, a large chisel which is used as a sword-like weapon. The sphere transforms and protrudes a long, dark metal bar tipped with a chisel cut, and the Sphere features a handle which can be used as a hilt. Gemini, transformed as Lucy, was shown utilizing Caelum in sword form, and has defeated Taurus with a blunt strike that sent Taurus flying in the air.

Cannon Form: In this form, it appears as a high tech cannon that can launch powerful blasts of energy, which was shown to incapacitate both Leo and Aries and send them back into the Celestial Spirit World in one shot.

Flight Form: In this form it appears as a simple winged sphere that has displayed mobility. This form has yet to display any offensive or defensive abilities.

Levitation: Caelum can levitate off the ground while in its default form, sword form and cannon form.

Immortality: As a Celestial Spirit, Caelum cannot die, unless it is forced to stay in the Human World somehow.

Fairy Tail Gekitotsu! Kardia Daiseidou
Caelum appears as a support character in DS Game Fairy Tail Gekitotsu! Kardia Daiseidou upon being unlocked. It is available in sword and cannon forms.

Major Battles

 * Lucy Heartfilia vs. Angel (owner)
 * Katja (owner) & Doranbolt vs. Racer