Veil is a Griffon, a legendary creature possessing the body, tail, and back legs of a lion combined with the head and wings of an eagle, often featuring eagle-like talons for front feet. She serves as the primary demon partner to Mirai Kaname, a fifth-grade student, and was initially sealed prior to the story's main events.

Summoned by Mirai for rescue from an attacking Ratatoskr demon, Veil initially displays a strong aversion to humans, particularly resenting their perception or treatment of her as a toy. This hostility lessens over time due to Mirai's actions, especially when Mirai saves Veil's younger sister, Hippogriff, and defeats the demons responsible for sealing both siblings. This event triggers Veil's gradual acceptance of humans, particularly Mirai, marking a significant shift in her demeanor.

Veil specializes in wind-based magic and provides practical assistance during traversal across hazardous environments, such as hovering above obstacles like icy terrain and shifting sands while carrying Mirai. Her role extends beyond physical support to active participation in battles against antagonistic forces, including those aligned with Lucifer, who seeks dominion over both the human world and the demon-inhabited Expanse.

While the anime adaptation features a distinct storyline, Veil remains Mirai's steadfast companion, collaborating with allies like Cool and Jack Frost to counter demonic threats destabilizing both worlds. Her identity as a Griffon and her evolving bond with Mirai persist in this narrative iteration.

In later game installments, such as White Book, Veil becomes transferable to Masaki Kuzuha's team after the main storyline's completion. She starts at level one and requires return to Mirai before further demon exchanges can occur, highlighting her recurring utility across interconnected narratives.