Viser was a young woman with a voluptuous figure with short white hair but her lower body was gigantic and beastly with four legs, each having sharp claws, and a snake as a tail. Her overall appearance was reminiscent to that of a Centaur.
In the anime, Viser still retained her voluptuous upper body, although her short white hair is replaced with long, black hair. Her centaur-like appearance has also been slightly altered, with her front legs featuring humanoid hands with red claws (the same color as her sharp nails) and her stomach featuring a cavity with teeth to devour her opponents. In the middle of her battle with the Occult Research Club, her face changed bearing piranha-like teeth, pointed ears, and black sclera in place of the usual white. 
Viser was a ruthless Devil who had an extreme lust for blood, evidenced through her introductory speech. In the anime, she shows some exhibitionist traits, rubbing her bare breasts in pleasure in front of her combatants.
Not much was known about Viser, other than at some point she was likely reincarnated into a Devil, and left her master and started to consume human bodies for food.
Viser was introduced in the Volume 1 of the light novel when Rias and Occult Research Club were ordered to dispose of her because of her actions. During the battle, she was incapacitated by Yuuto (cutting her arms off), Koneko (punching her in the stomach), and Akeno (electrocuting her with lightning). Overwhelmed by their power, she was soon confronted by Rias, whom she asks to kill her. Complying with her last words, Rias terminates her using her Power of Destruction.
Spear: Viser wields two spears that appear to be strong enough to pierce the ground.
Powers & Abilities
Enhanced Strength: Viser's monster-like lower body possessed superhuman strength, shown when she manages to briefly hold down Koneko.
Demonic Power: As a Stray Devil, Viser possesses demonic power. She also fights with two spear-like objects.
- Breast Acid: In the anime, she has the ability to squirt acid from her breasts that can melt walls (with magic circles appearing on her nipples prior to firing), and has the ability to consume her opponents using her stomach cavity from her Centaur body .
- Viser was the first stray devil introduced in the series.
- "I smell something bad. But I also smell something delicious. I wonder if it's sweet, or if it's bitter?" (Volume 1, Life 2)
- (To Rias) "You are cunning for a little girl!! I will rip your body and color it in red just like your hair!!" (Volume 1, Life 2)
- Highschool DxD Light Novel Volume 1 Life 2 Part 8
- Highschool DxD Anime Season 1 Episode 3