In the novella "Prince of Crows" Captain Alastor Rushal from the Raven Claws. Who joined the Night Lords after the events of the Dropdrop site massacre on Isstvan 5. It is unknown however if he did so willingly or not. This excerpt from Prince of crows tells that he was a Captain of the Raven Claws before joining the Night Lords and scratching away the marks and disgracing the markings to his former allegiance. (Emphasis mine)
During the Second battle of Prospero a group of White Scars Legionnaires from a warrior lodge within the legion led by Hasik Noyan-Khan and Torghun Khan where they attempted to lead their group of heretical white scars to take control of the White Scars' fleet and join the Death Guard led by Mortarion at the time whilswhile Jaghatai Khan was on prosperroProspero at that time. The plan failed however when Shiban Khan managed to board the White Scars Flagflag ship the SwordStorm, Swordstorm.
‘Brothers, Hasik Noyan-Khan has control of the Swordstorm Swordstorm. From there he controls the Legion in the the Khagan’s absence. He must not be allowed to make the decision for us. That is why I have called you you here. It means assuming the mantle of renegades, at least in the eyes of those who now seek to subvert subvert us. It means taking up arms against our own brothers. You do not need me to tell you that no such rebellion has ever occurred inside the White Scars. We risk our honour, and may pay for it with our our lives.’ Shiban
Shiban clutched the hilt of his glaive tightly. ‘I ‘I cannot demand this of you. We will not be fighting xenos – these are our own people. All I can do is is ask you to trust me. I have led you across the arc of the galaxy in the cause of the Great Crusade. We We have brought compliance to hundreds of worlds and given honour to the name “White Scar”. You followed followed me then. Brothers, you have heard what I judge to be true.’ He
He paused for a heartbeat. ‘Will ‘Will you follow me now?’
The Khan strode down from the platform, his keshig following him closely. Ahead of him, the command command hall remained swamped in combat. Many of those close enough to the teleportation flare to hear hear it over the clamour of the fighting broke off in sudden confusion, but others remained committed committed, locked in the storm of bolt-shells that crisscrossed the entire space. For a terrible moment, the Khan witnessed the warriors of his Legion at each other’s throats. Mortarion’s Mortarion’s words rang in his head, as mocking as that final salute. Half Half your Legion are already declared for Horus. He He scanned over to the command throne. The fighting was heaviest there. With a lurch of recognition recognition, he saw Hasik occupying the dais, fighting hard to repel a surge from Jemulan’s warriors warriors.
When he arrived MOST of the white scarsWhite Scars surrendered.