From Destinypedia, the Destiny wiki
Revenant Knights are the Elite variant of the Knight seen throughout Savathûn's Brood. They can be distinguished from their Minor counterparts by their white body paint and cloth or their dark and partially gold chitin. In Shadowkeep, the Hidden Swarm also employ these Knights, bearing beige chitin and red body paint. In The Witch Queen, the Lucent Brood also have Revenant Knights among their ranks, distinguishable by their gray coloration.
List of appearances