Devilun is an angel whose form mirrors that of a Tasmanian devil. This angel seeks out Kurumi Azuchimomoyama, a fourteen-year-old girl, and bestows upon her the power to transform into the magical girl dinosaur angel warrior Prima Pink. Devilun charges her with the mission to combat the evil organization known as the Darkness Whales.

Speaking with a foul mouth and demonstrating a particular skill for information technology, Devilun sustains itself on a diet of wild rats and crows. The angel also works to recruit other girls into becoming Prima Angels, such as Mizuki Sangenshoku, whom Kurumi is able to convince to join their cause.

An awakened state exists for Devilun, a condition in which its voice becomes noticeably sweeter and grows far more talkative than in its normal state.