Black Rose

Black Rose was a chemical weapon developed by the Garlean Empire in Gyr Abania in order to conquer their enemies in Eorzea. The chemical was an easily deployed weapon that would infuse the Aether of all who inhaled it with massive quantities of Light, bringing it to a standstill and killing them. The weapon was incredibly effective, leaving no mark or trace on its victims. The weapon was originally decommissioned by Gaius van Baelsar, as it was a weapon of death and not conquest, ordering the remaining compound to be destroyed. However, when Elidibus possessed the deceased body of Zenos yae Galvus, he restarted the project, testing it on the Ala Mhigan Resistance members.

The new stock was eventually discovered and destroyed by Estinien Wyrmblood and Gaius, after the latter found entire camps of resistance members wiped out without so much as a struggle. In an effort to increase the effectiveness of Black Rose, the Ascians enacted a plan on The First to flood the world with Light, which would bleed into The Source, causing the Eighth Umbral Calamity, however these efforts were stopped by Minfilia, who prevented the Flood of Light from consuming Norvrandt.

In an alternate timeline, the Ascians were successful in destroying the First, and the Empire released Black Rose, killing a majority of the population of not only Eorzea, but most of the Three Great Continents, the Warrior of Light and the Scions of the Seventh Dawn among those who had fallen. To prevent this fate from coming to pass, G'raha Tia, using the Crystal Tower and the work of Cid nan Garlond, traveled back in time to the First to do what he could to prevent the world from being lost to Light, thereby never allowing Black Rose to reach its full deadly potential.