Viper

"Ballistics for which you can choose the trajectory: Viper."

- Shiori Usami on Viper.

Viper is a Gunner Trigger.

Appearance
Once shot, Viper appears as a luminous trail that, due to its properties, often resembles a zigzag. The size of each bullet is directly proportional to the amount of trion the user has. Gunners fire Viper bullets through different types of gun-shaped Triggers, whereas Shooters form a trion cube that can be divided in smaller regular polyhedrons, their size and shape depending on how many are created at once.

Overview
The origins of this Trigger are unknown. It was first used by Shooters only, until firearm Triggers were invented.[BBF Q156]

Abilities
The main feature of Viper is it allows users to form trajectories for the bullets before shooting. However, it is easier to come up with patterns in advance and then choose whichever one is needed. Izumi and Nasu are the only Shooters that can create formations spontaneously.

Trivia

 * Like other Gunner Triggers, Viper may have been named after a missile, the AGM-80 Viper, whose system offered fire-and-forget performance.
 * The viper is a family of venomous snakes. Snakes have many vertebrae which allow for increased flexibility, which is similar to how this Trigger is flexible in changing trajectory.