From Destinypedia, the Destiny wiki
The Deathless Aspirants can appear during the Enthymeme and Chiasmus encounters. They fight just like any other Abomination of their kind and spawn on the three different sides of the room. During the encounter, players must kill Scorn in order to lure out an Aspirant. Once the Aspirant is slain, more Scorn will appear at a different side of the room. Repeat this process until all three of the Aspirants are slain. Once the Deathless Aspirants are slain the encounter is complete.