Scorcher

"Scorcher" was code-name for a planet-destroying super-weapon used by the Gudersnipe Foundation during the Mage Wars and remained in service for an indeterminate amount of time during the Ages of the Alliance (estimated to sometime into the Fourth Age). Scorchers were never deployed after B.G.A. 17.

Device

Though referred to as a "planet-killer", the scorcher was actually completely incapable of destroying a planet and in fact was not intended to do so. The purpose of the weapon was, as nearly instantly as possible, to render a planet incapable of supporting life. The mechanism involved simultaneous detonation of several thousand N1.5 devices just above the troposphere. If all went according to plan, the chain reaction would be enough to flash-boil the oceans and set the atmosphere on fire.

The excessive heat and concussive force was enough to knock most of the gasses away from the planet surface. Any atmosphere that remained was thin and poisonous. Even the most sophisticated bomb shelters typically could not last long in such an environment.