History of Xûr's Chosen

Xûr's Chosen, Special Guest Star is an optional, cloaked Taken Minotaur that can spawn during the Lightning Round of Dares of Eternity. Defeating it is not required to finish the round and drops no extra loot. Its kills count only toward progress on a triumph.

Sources disagree on how many kills the triumph needs, so check a current guide before planning around it.