Betrayer

"'Saving your people will not bring you peace, only makes the burden you carry worse.'- The Betrayer to the Doom Slayer."

The Betrayer is the former member of the Night Sentinels that committed treason against the realm to bring back his dead son. He is one of the supporting characters in Doom Eternal.

Doom Eternal
The Doom Slayer meets the Betrayer to retrieve the Celestial Locator to track down and kill all the Hell Priests to destabilize hell force on Earth.