Mithrax, the Forsaken
Mithrax, the Forsaken is a former Captain of the House of Dusk who later founded the House of Light, having decided to ally with the Guardians of The Last City following an encounter with The Young Wolf.
Meeting with Sjur
At one point Mithrax, then a Vandal of the House of Wolves, was held in captivity by Sjur Eido. After a failed attempt at escaping her clutches and trying to commit suicide, Sjur befriends the captive Fallen by performing a traditional Eliksni display of armistice much to Mithrax's surprise. As they exchange names and Misraaks becomes Mithrax, he is introduced to the Dreaming City. Sjur becomes so renowned among the Eliksni they called her Siyuriks pak Variisis ("Sjur, the Unyielding") and forms an early alliance by giving Amethyst crystals as political gifts to their Archons.
Enemy Of My Enemy
After the SIVA Crisis, Mithrax would leave his wolf-born house and join the House of Dusk along with the remainder of his Fallen brethren. Guardians will encounter Mithrax and his crew in Chances and Choices as both parties compete to access an ancient methane reactor. Various Barricade Servitors and the High Servitor Selkis, the Obstructor are put in the way to prevent the Guardians from reaching the core, along with local Hive forces swarming the complex attacking both. Mithrax is later seen dueling against a Hive Knight in which Guardians are given a choice in who to kill. Killing the Hive Knight and sparing Mithrax will trigger an alternative ending in which he'll thank the Guardians with an Eliksni display of respect similar to Sjur's ages ago. He disappears and grants the player access to the reactor.
Alliance with the Guardians
While not physically appearing in Forsaken, sparing him is revealed to be the canon choice; Having been touched by Sjur's display of humility and the Guardians' mercy, he defects from the House of Dusk and swears allegiance to the Last City, eventually joining a fireteam of Guardians. He has also founded the unofficial House of Light to lead the more open-minded Eliksni as their Kell, arguing for the sake that humanity, not the Fallen, have proven befitting of the Traveler and its gifts. 
Later on, in the Season of the Drifter, Mithrax beckons Guardians to The Farm using a Fallen Transponder. Interacting with Mithrax takes both him and The Guardian to the Old Tower to complete the mission Zero Hour where they chase down House of Devils loyalists who have stolen preserved SIVA tech from a Cryptarch Vault deep inside. The group is in search of the weapon known as Outbreak Perfected, a Destiny 2 version of the famed Rise of Iron weapon, Outbreak Prime. Led by Siriks, Loyal to Eramis, the group is defeated before they could escape The Last City. After Siriks is defeated, Mithrax jumps onto a Fallen Skiff and once again disappears.
List of appearances