Crux

Caelum the "Chisel" is a Celestial Spirit owned by Lucy Heartfilia. It is unknown if Crux can fight, however Crux has the ability to search for information Celestial Spirits and their owners by sleeping.

Loke arc
Crux is summoned by Lucy to see if Loke had any history with a Celestial mage before. During his meditation he found that Loke once knew Karen Lilica but he didn't divulge that Loke was really Leo.

Magic & Abilities
Scanning: Crux can scan past people who have been in contact with Celestial Spirits and Celesitial mages by sleeping.