Rassei is a noticeably small Dragon, with blue diamond-like scales and a small pair of wings.
According to the Familiar Master, a Sprite Dragon needs to be tamed as a child or else they will become uncontrollable as adults. Rassei is especially protective of Asia and it has been shown that he can get very jealous, as shown when he electrocutes Issei when he gets close to Asia in his presence.
Not much is known about Rassei except that he was born in the forest where many other familiars live.
Originally an unnamed Sprite Dragon, he was first seen in the side story "The Familiar's Requirement", where he destroys the slime and tentacles that were covering Asia and electrocutes both Issei and Yuuto (only Issei in the anime), much to their dismay. When Issei attempted to attack him, Asia stops Issei as Asia contracts with the Sprite Dragon, naming him Rassei.
Rassei appears in Volume 14 when Asia is asking Ophis on how to communicate with Dragons.
Powers & Abilities
Lightning: Rassei can generate blue lightning. The blue lightning he generates is powerful enough to stun a Low-Class Devil.
Flight: As a Dragon, Rassei has the natural ability to fly with his small wings.
- Rassei's name is a portmanteau of Raigeki (雷撃, meaning "Lightning Strike", referring to its ability) and Issei's name.