Crimson River.
A term that simply meant Pool of Blood, or, to make things less poetic, a mass murder... Genocide.
It was an operation created in the shadows by one of the rogue Meisters of the past Council. It involved a banished act that would completely wipe all Bearers off the face of the earth.
The rogue Mage's strategy involved targeting Essence. And since Bearers depended on Essence rather than their life forms, by extinguishing Essence, Bearers will inherently be exterminated as well.
The Mage made it clear that this operation was only to be attempted in a situation where the Bearer inflation has gotten so high that the Continent's existence becomes at risk. Nevertheless, the rest of the Council had rejected and banished it.
Crimson River was a forbidden act. If High Meister Gavryndor wanted, he could strip Meister Khaul of his powers for just mentioning it.