Brother Guts. The Black Sword man. Demon slayer Primaris who have Chaos mark on his neck.
Urizen Inquisitor
"As the Urizen recorded, Lupercal did slay the Demon Sanguinius and, with the last of his strength did he vanquish the False Emperor, as we must vanquish his remaining followers to preserve this great empire."
"The Khorne accountant; a high demon of Khorne angry with a berserker for not bringing enough skulls this month."