Kasi has dull tan fur with light grey paws, underbelly and muzzle. Her eyes are blue. Her nose is pink and pointed, her inner ears are dark and light brown, and she has a large tuft of fur on her head. She has three large, light brown markings placed on her sides, just after her ribs. Her tail tip is brown.
Kasi has a very thin and lithe build, being much thinner than the other lionesses and more flexible. This helps her run incredibly fast and make it through a set of twists and turns at speed.
Kasi is serious and very confident. She used to be a member of Zira's Pride, and upon joining Simba's pride, she's become the fastest member of Vitani's Lion Guard.
When Kion his Lion Guard and multiple Outlanders are runing to to stop Zira, Vitani's Guard comes to stop them. Soon Kiara comes to stop them from fighting, and Kovu explains that Zira has completed her journey through the Circle of Life.
The next day in the Lair of the Lion Guard Vitani's Guard starts fighting with Kion's Guard. Laini interupts them and says that there's an emergency at Mbali Fields. Thurston is stuck in a hole while the two guards fight. Azaad helps him. Thurston soon suggets of having a competition to see who's the better Lion Guard. Kasi face off agaisnt Fuli. However, Kasi loses in the race and Fuli wins.
After four events it's up to Vitani and Kion. Vitani calls for a Mashindano against Kion, but Kion soon decides that Vitani's Guard wins and Vitani gets the Roar of the Elders.
Kasi is the last new character to make a debut in Season 3 and the season finale.