Ghost: Mercury was transformed by the Vex in the early days of the Collapse. As far as we know, the Warlock Osiris is the only Guardian to spend any time among the spires. And we haven't heard from him in years.
Commander Zavala: Osiris brokered a contract between the Sunbreakers and the City. Its terms were… unacceptable to me. Now, the Sunbreakers hate the Vanguard. They… hate me.
The Burning Shrine, Fields of Glass, Mercury
The Guardian arrives at the Burning Forge.
Ouros: We do not know of you, Guardian. But if you found us, you are worthy of our time. I am Ouros, Third Empyreal Magistrate of the Sunbreakers. You have come to test your Light in the forge. Here you must prove you are one with the Light. Use your Ghost to ignite the forge.
Ghost: Yes, ma'am. Guardian, Ouros is a legend. If even half the stories are true, she's one of the most powerful Titans alive today!
The Guardian defeats the Vex which appear while Ghost restores power to the array.
Ghost: Power's on, but the array needs to be aligned. Let's head outside.
Ghost refocuses the array's beam.
Ouros: In the shadow of the Light that gave birth to the ancients, use the forge.
The Guardian approaches the Burning Forge.
Ouros: Fire born of man. Fire of the Light. Ask yourself, what power do you seek from the forge, Guardian? Can you bring Light to where only Darkness survives?
The Guardian is sheathed in flames as they forge their own Hammer of Sol.
Ouros: Prepare yourself.
Ghost: So, we're going to get attacked then. Here we go!
Multiple waves of Vex appear. The Guardian uses the Hammer of Sol to defeat the Vex.
Ouros: A Sunbreaker does not answer to any but the will of the Light. Welcome, Guardian. Wield no power but the fury of fire.
Hall of Guardians, The Last City, Earth
Zavala: A Sunbreaker's fire has not been seen within the Walls in years. Take that hammer to the stars, Titan. It represents the Tower now.
The Guardian receives a Sunbreaker's Mark.