Sunbreaker is a Titansubclass in the Destiny expansion The Taken King. It is obtained after completing the questThe Sunbreakers' Challenge. The Sunbreaker is unique among Titans in that unlike Striker and Defender, this subclass grants a ranged Super attack that, with certain modifiers like Scorched Earth and Explosive Pyre, can excel in crowd control and area denial without running the risk of being forced into close quarters combat.
The Sunbreaker order of Titans predates the rise of the City. They have never desired the safety of the City, and they eventually left to create a stronghold on Mercury, where they live as mercenaries. At some point, the Sunbreakers struck a deal with Osiris but Zavala did not agree with the terms, which led to them hating the Vanguard as a whole and Zavala specifically.