Kelsa is a member of the Shi family, and part of the Wei clan. She is the sister of Wei Shi Lindon, who is the protagonist of the story. She is on the Path of the White Fox.
"Just like the rest of her family, she was tall and intense, but where Lindon tended to look like he was contemplating a murder, Kelsa gave off the impression that she was always giving you one hundred percent of her attention. No matter what was happening." (Reaper)
Kelsa lives in the Wei clan along with the rest of the Shi family as a Copper on the path of the White Fox. She is considered the pride of the family. After Lindon returns with a spirit-fruit from an ancestral tree, the family argues for Kelsa to receive the whole fruit in order to advance her quickly to Iron in time for an upcoming tournament with the other clans of Sacred Valley. Kelsa instead divides the fruit in half, giving the other half to Lindon.
Days later, before the tournament, Kelsa advances to Iron while sparring with Lindon.
It is revealed that Kelsa survived the destruction of the Wei clan. She is on the run, either by herself, or with a number of Wei clan survivors. She has been stealing food from the Heaven's Glory and Fallen Leaf Schools in order to survive.
While on the run from several hostile Irons, Kelsa encounters Orthos, who reveals that her brother is alive. Orthos then protects Kelsa from the pursuing Irons.
Wintersteel and Bloodline
Kelsa fights to feed her blind and lame father and free captives in Sacred Valley, especially her mother. She is helped by Orthos, Jai Long and Jai Chen. She is retrained in basic sacred arts by Orthos. In Bloodline, they are under attack by numerous jades and irons. They are defended by Wei Shi Lindon Arelius, her brother. He takes them to safety before the dreadgod Titan arrives in Sacred Valley.
Kelsa and her family live with Lindon on Windfall. Kelsa is romantically interested in Jai Long and friends with his sister, Jai Chen. Along with Jai Chen, she helps recruit and organize the Sect of Twin Stars. With guidance from Orthos and Lindon, and after sparring repeatedly with Little Blue, she has advanced to Lowgold. It is difficult for her to control her goldsign -- a foxtail of purple-white foxfire. She fights for the Blackflame Empire in the battle Monarch Reigan Shen arranged on the slopes of Sacred Valley. Her squad leader is Jai Long.