Avinia (Japanese アユリア) is a young monster rider known to ride on her Barioth, Frostfang (Japanese ヒョウガ). She resides in Kuan Village.

Upon first encounter, Avinia portrays a cautious if not distrustful personality who tries to hide her feelings. However, she is shown to be kind and loyal to those she acknowledges as her friends. She shares a close bond with her Monstie, Frostfang.

Like the Player Character, Avinia originally came from a village of Riders that isolated itself from the world. Her village was tragically destroyed by the Black Blight and left it along with her Monstie, Frostfang. She would then seek out the Channeler to perform the Rite of Channeling until she is attacked by a Khezu and flees until she is saved by the Player Character.

In Monster Hunter Stories 2: Wings of Ruin, Avinia returns as a companion to the new Player Character. After the events of the first game, she takes part in the rebuilding of her home, Kuan Village. The sequel also reveals how she met and befriended Frostfrang.