Vanguard tears

Vanguard tears are a potent, black/red liquid, initially provided to the apex by the Vanguards with the promise of power enough to defeat an awakened being. Vanguard tears are applied to a cut or ingested, turning humans into feeders, corrupting yoma into berserker, or rapidly increasing the seasoning of an awakened. The tears have irreversible side effects, feeders loose their minds can never become humans again, berserker yoma loose their minds (and all their muscle mass upon death), and awakened loose their yoki as it is burned through, reverting to humans and quickly dying.

Vanguard tears are all Quantity and no Quality. This potent mixture causes an enormous overload of power to whatever drinks the tears. However, due to the impurity (lack of quality) the tears have, and their enormous quantity, the power of the tears rips apart the egos of those using it, destroying their minds and causing intense physical power. Humans, with no quality to start with, are instantly turned into mindless feeders after drinking the tears while awakened, with higher qualities, can resist the turn to mindlessness far longer, although the power begins to wear away at their minds as the chaotic, impure tears merge with their purer yokis, reducing their quality to the point they turn into mindless dolls.

Vanguard tears were replaced with the less potent tears of fear, which have enough quality to retain some portion of the original being's mind and create unique, inhuman forms in those that drink it..