Viper

Viper's abilities use gas and fuel:

• Toxic Screen (signature): a line of emitters that passes through walls and, when activated, raises a wall of gas along its whole length. It blocks vision and weakens anyone crossing it;
• Poison Cloud: an emitter you throw that, when activated, creates a gas cloud. It can be switched on and off;
• Snake Bite: an acid pool that damages anyone standing in it and makes them vulnerable (they take more damage);
• Viper's Pit (ultimate): a big cloud covering a wide area; enemies inside see very little and take poison, while Viper moves through it to her advantage.

The wall and the cloud consume fuel: when you switch them off, the fuel recharges. Managing fuel, deciding when to keep the gas up and when to drop it, is a big part of playing Viper.

Pick Viper when:

• the map has big sites and long lines, where a wall cutting the site in two does more than any round smoke;
• the team wants a controller who is strong in the post-plant: Snake Bite and the ultimate make defusing very hard, often with lineups from range;
• you need a controller who delays for a long time: the wall and the cloud can be switched on again, and a Viper can hold a site with gas for a long time;
• the team already has a controller with round smokes and needs a second controller with a wall.

Viper is also a great pick for players who like preparing rounds: lineups, wall placements, cloud spots. Her value grows a lot with study.

Another advantage of Viper is her constant presence: the wall and the cloud can be switched on several times in the same round, and a defense with a well-prepared Viper forces the attack to deal with gas in every phase, not just at the start.