Chemical weapons
Chemical weapons use the toxic properties of certain substances (usually gas) to kill, incapacitate, or damage the enemy. Use of such weapons are banned under the Hosluftgrad Conventions. Historically, they have often been used by a force whose opponent outmatched them in conventional firepower.
Chemical weapon agents
Early chemical weapons included chlorine gas and mustard gas. Chlorine gas was relatively easy to defend against. It formed a visible green cloud and strong odor, and was soluble in water; simply covering the mouth and nose with a damp cloth was adequate defense. Mustard gas, which caused blisters on the skin, proved much more useful. Mustard gas, it should be noted, is mainly an incapacitating agent, lethal in only a small percentage of cases. Mustard gas also tended to linger in the area it was deployed, making it an effective area-denial weapon.
The Dark Wrath, is it were, ‘set the standard’ with a poison gas known simply as “Dark Wrath Poison Gas”. (Ironically, it was often deployed an its original volatile liquid form, which quickly evaporated). Dark Wrath Poison Gas was highly lethal, even through contact with the skin, but tended to disperse quickly, allowing advancing Dark Wrath soldiers to seize territory and equipment. The Dark Wrath also developed chemical weapons that were more persistent and defoliants for use against resistance movements in the Dragon Dimension and Ticondera, the idea being to poison whole towns and tracts of land to render ‘smoke’ the rebels out. It is these weapons that have left much of the Dragon Dimension infertile and unusable.
The Celpo, not to be outdone, began experimenting with chemical weapons and developed a variety of neurotoxins; Celpo needle weapons are tipped with a fast-acting neurotoxin that makes even a grazing shot instantly fatal. They also began experimenting with combining radioactive properties into chemical weapons; M-Doom was the result.
Radioactive gases are an avenue of research continued by the Viper District, which created DW-R, a variant on Dark Wrath poison gases that distributed highly radioactive isotopes in the atmosphere. This is a particularly promising avenue of research because heavy metals often actually increase the radioactive dosage rather than providing protection. (Electrons from the radioactive source cause the heavy metal to emit X-ray photons.) In effect, DW-R is much more effective against vehicles than normal weapons. The Viper District used this weapon to blunt the Scandian/FTSR offensive into their territory.
Another recent development is the creation of horrifying laughing gases believed to be of Foolish origin. Some of these simply cause short-term incapacitation through uncontrollable laughter; some of the more sinister variants actually cause long term dementia.
The Grand Army continues research and development of chemical weapons, ostensibly to help perfect defenses against them. Various Great Powers may or may not continue development of these weapons. Although officially the possession and use of these weapons are a violation of the Hosluftgrad Conventions, some chemicals used in these weapons have legitimate industrial uses, and so policing this particular branch of weapons of mass destruction is much trickier than policing Ultima missiles.
Deployment
The easiest way to deploy chemical weapons is to simply open canisters of gas upwind of your opponent. Often, magic users such as Blue mages or Mana mages specializing in Sylphid will be employed to ensure favorable winds. The most common and simple way, however, is to distribute the gas through the detonation of a bomb or artillery shell. Covert operatives have been used to plant chemical agents in important areas, such a city’s central water supply. Halder Skalice in the Leviathan War used Assault Engineers to deploy the gas canisters underneath the Returners Expeditionary Force.
Limitations
Wind and weather can disburse certain chemical agents very quickly. In an era where many soldiers have fully environmentally sealed battlesuits, and others operate in similarly protected vehicles and mecha, chemical weapons have limited utility against an opposing military force. However, they are extraordinarily useful against local resistance forces and guerillas who may not have access to such technology. The fact that chemical weapons are mainly useful against civilian targets and as a terror weapon was a significant factor in banning them.