Rosie

Past Timeline
Rosie's real name is Osis, a member of the imperial knights of the Skytria Empire 1,500 years ago. During this time she was the sister of Mojave (Redisands in Korean webtoon) and was tasked in finding black magic locations in Skytria. Eventually she realized the magic traces were leading to Claudia. The Silversword family realized Claudia was practicing black magic and putting the empire in danger. Snolled/Dellons was unaware of this and fought against Mojave and killed him. Claudia's sister, Arial, then suddenly stabs Claudia and kills her. Osis, furious about Mojave's death, goes and kills Snolled too. The Silverswords lied and accused Snolled of murdering Claudia and kept it a secret of what truly happened. She becomes one of the Seven Knights after receiving praise for killing Claudia's 'murderer'. After some time, Osis became filled with guilt for all deaths she had caused throughout her years. She becomes very regretful for her past actions. She decides to leave her former life and name behind and goes to a monastery to repent for her sins and pray to the Goddess, Elena. She uses the name Rosie to try to keep her real identity a secret. She meets a member of the monastery named Rofus and befriends him. Eventually Dellons wakes up after Bai Jiao recovers his memory and Dellons goes on a hunt to kill the Silversword family, he finds out that Osis is using a fake name under Rosie. One day a massacre happens in the monastery where all people are killed except one nun (Rosie). Rosie realizes it was Dellons because of the scythe traces and goes down to hunt him.

Season 4
She falls into a trap by Dellons and is sealed in the abyss. When the power of the abyss spreads across the world, the seal is broken and Rosie is released. Rosie decides to hunt down Dellons and to kill him once and for all.

Trivia

 * Her real name is Oasis Silversword.
 * She was a member of the silversword family, ancestors to kris. It is believed the ancestors of the silversword family were elves.
 * Even though she's physically young, Rosie comes from an era 1,500 years old.
 * She was the first new special hero to not come out with a teaser or trailer.

Season 4

 * Kris: "Silversword..."
 * Dellons: "You can't run away from me".