Hermanus of Tremere
Lived from 940-1098: his final fate is obscure but believed to be Final Twilight. A few facts are known throughout the Order: a veteran of the Schism War, he worked to improve the magical defences of Coeris and other House Tremere covenants, and as an astute politician managed to have a surprising number of resources dedicated to that aim. His final undoing is popularly said to have been due to House Diedne sympathisers within House Tremere.
Hermanus is subject of a chapter of Legends of Hermes.