Quintessence is a name given to a mysterious substance which was discovered almost at the beginning of the game's history deep in an isolated desert by a group of priestesses from the Land Across the Seas. Originally, it had no particular shape, resembling a huge flow of ethereal energy. Each priestess consumed a portion of the Quintessence, which in turn gave them heightened speed and reflexes, and the ability to shapeshift to any living creature, man and beast. Considering it sacred, they transported the Quintessence to their land and kept it safe in a pyramid-like temple. There, ordinary people gathered and worshipped the priestesses, viewing them as gods. Some unspecified time later, a legion of Aerian soldiers arrived at the Land Across the Seas, taking what had remained of the quintessence by force. Back in Aeria, they hire the Arch-Alchemist Alden Laeril to extract the Quintessence to an edible form. Alden succeeds, and the result is a glowing pill. But since this new form of Quintessence has lost its purity, there are two kinds of venom embedded within the pills, giving them extremely lethal qualities. Alden successfully manages to cleanse the first venom, but due to his abandoning the research on the Quintessence in a premature stage, the second venom remains inside. Even then, the pills have lethal qualities, which shorten the life of their consumers to a great degree, acting as a certain death warrant.
Quintessence, in its pure form, grants its consumers hightened speed and reflexes, as well as the ability to shapeshift to any living crature, whether it be human or animal. Its extracted pill form, however, has far less power compared to its pure form, as well as being deadly in the long term. For instance, while retaining the quality of hightening the consumer's speed and reflexes and the ability to shapeshift, it does not enable the user to turn to animal forms, and infects them with a venom that gradually wears their bodies down, guaranteeing an early death. Although generally thought to be beyond cure, the venom is supposed by a few to be curable, though it is only a theory, and the potential answer lies in the Land Across the Seas, the very first place where Quintessence was discovered long ago.