Galanthus

Auril
Galanthus was a simple adventurer. They traveled the Sickle, sword in hand, trying to help out those who were in need. In those days, they had a different name.

On one journey, they were searching an ancient barrows, trying to find the source of a peculiar haunt. What they discovered was a shrine to Auril(placeholder name), a forgotten deity of Winter. This winter goddess pleaded for Galanthus to become her saint, her hand in the world, so perhaps she could reclaim some of her ancient divinity. Galanthus, out of a sincere desire to help others, accepted this offer. Auril bestowed upon them their new name as Champion of Winter.

So Galanthus had taken their paladin's oath, but they were still a normal, uncorrupted human.

The Party
After taking their oath, Galanthus met up with a party of three other adventurers, and they went on a few adventures, growing in power, until...

Chult
On a quest direct from Auril herself, the party attempted to traverse the jungles of Chult to find Artus Cimber, who Auril informed them was an evil man with a powerful artifact. The party found the jungle to be a harsh and deadly environment, and all but Galanthus themself perished. Galanthus arrived at the Lost City alone. There they met another party of adventurers who had just defeated the Soulmonger.

The Ring of Winter
With this new party, Galanthus was able to defeat Artus Cimber and claim the Ring of Winter for themself. When the Ring tried to take control of Galanthus, Auril fulfilled the final stage in her plan. She imposed her own will on the Ring; she had control of it, and she then used the Ring's own properties to take complete control of Galanthus.