You know, Chyllaen was only an Aes Calon once. Now they are the Master of Aes Calon, a deity in their own right!
Chyllaen is the An Náduri deity of cunning.
How the spirits came to be is a mystery which has eluded everyone, yet here they are. The first and most powerful of the spirits came at the end of the First Age. Though none came anywhere close to the power wielded by a deity, these spirits lingered in mortal realms and were by far the most powerful entities there. Their notoriously mischievous nature combined with the power to wreak havoc soon became an issue for the mortals, thus drawing the attention of some of the local deities.
Before they could do anything about this new issue, however, one of the spirits was seen to be a benevolent force. The deities chose to wait awhile and soon saw more such spirits appear. These spirits came to be known as Aes Calon and though they had the same unpredictable nature as all other spirits, Aes Calon and mortal-kind worked together to solve the issue of the malicious spirits themselves.
During the Fourth Age, the deities were concerned they would have to intervene as a particularly powerful young spirit rose but they stayed their hand for the spirit did more good than evil. After the deaths at the end of the Sixth Age of the local deities who were keeping an eye on them, Chyllaen seized the chance to become a deity themself. Chyllaen still retained all their Aes Calon talents, skills and quirks and soon became known as a kind being despite their reputation.
A deity similar to Chyllaen, named Kyllaen, is worshipped by the elves of Tumeland, and is likely the same.