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. Avinia originally came from a Kuan Village that isolated itself from the world, Kuan village is on a snowy mountains with hot-springs near by. 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 Jack back when she was young. Jack had also saved Avinia, after she had been captured by the Dark Riders. After defeating the Dark Riders, Jack and Avinia had gotten together. They loved each other greatly, until split ways because of their different wants. Avinia wanted to rebuild her village, while Jack wanted to explore the world. Years later she still takes part in the rebuilding of her home, Kuan Village, now all grown up. She still loves and misses Jack.

Avinia is young human woman with blue eyes and blonde hair tied in a ponytail. She wears a white armor similar to Barioth Armor. Her Kinship Stone is attached in the center of her chest. Avinia has slightly small breasts than Kirin. Avinia has ice powers.

Frostfang the Barioth is her only Monstie in both the anime and game. In the anime, it is granted a Dragon Element through the Rite of Channeling with her brother's Silver Rathalos, Dusk.

Barioth is a quadrupedal Flying Wyvern, with a head that resembles a saber-toothed cat. Its body is mostly covered with icy white plates and spikes along its neck, spine, and tail. Its face features two massive, curved tusks of an amber coloration. Its forelegs are longer and more powerful than its back legs, with deadly spikes along its wings, as well as three large claws. Barioth's tail is forked and ridged with spikes. Barioth is highly aggressive and territorial. It will attack any hunter that enters its domain. It will eat Popo or Anteka when fatigued. When in rage, Barioth's eyes will turn red.

Barioth can move quickly and attack wildly, presenting a challenge even to experienced hunters. Barioth uses its fangs and claws to slide around on the ice making it hard to keep up with. It is able to slide its tail to its side and wield it in a club-like fashion, which can cause the Iceblight status. It can use its claws and wings for a homing glide attack from the sky on unsuspecting prey. It is capable of producing a wind blast; Barioth will spit out an icy ball that will create a powerful tornado. If caught in this tornado, the hunter will be inflicted with the Snowman Status effect. However, this wind blast will not work while Barioth is fatigued. Barioth can and will perform side jumps and dodges, similar to other Pseudo wyverns.

Avinia uses the Bariguiro, a hunting horn that boosts attack, heals, and boosts affinity.