|This page contains spoilers for:||First and Only (Novel)|
After his father was executed by Commissar Ibram Gaunt, Flense's name, land and titles were stripped from him, and he was forced to make his way through the ranks of the Imperial Guard as a common soldier. Seventeen years after Dercius' execution, Flense was a Colonel of the Patricians, and his regiment was deployed in the Sabbat Worlds Crusade alongside the Tanith First and Only, which was under Gaunt's command. Flense and his men took every opportunity they could to undermine or destroy the Ghosts in general, and Gaunt in particular.
During the battle of Menazoid Epsilon, Flense confronted Gaunt in single combat, seeking to avenge Dercius's execution (and thus, his own disgrace). However, before he could strike the killing blow, Gaunt killed Flense with his Tanith dagger; the majority of the Patricians who had accompanied him were either killed in the battle or by Gaunt's troops.