While he was still a Vandal in the House of Wolves, Mithrax was jailed by Sjur Eido. Sjur, who had some knowledge of the Eliksni language, was able to communicate with him.¹

Based on his appearance during his first encounters with the Guardian, Mithrax likely became a member of the House of Dusk.²

Around the time of the Red War, Mithrax and other Fallen from the House of Dusk attempted to steal a methane reactor from a site on Titan.³ However, when confronted, Mithrax instead chose to hand the reactor over to the Guardian.²

Mithrax also formed a fireteam with two Guardians. While on a journey with them, Mithrax expressed a desire to unite the Eliksni under one banner.⁴ At some point, Mithrax founded House Light and became its Kell.⁵

Following her escape from the Prison of Elders, Eramis, who was still a Devil, hatched a plot to steal a SIVA weapon from the City’s old Tower. Mithrax became aware of this plot and alerted the Guardian, who traveled to the old Tower to recover the weapon.⁶ He also infiltrated the Devils’ heist in order to assist the Guardian in their mission.⁷

Prior to the House of Salvation’s formation on Europa, Vanguard intelligence released a report regarding a number of potential leaders of Fallen “reunification efforts.” One such possible leader was Mithrax, who was reported to be assisting Guardians in the field.⁵

In an intelligence report made before the Guardian’s journey to Europa, agent CHA-319 reported that Mithrax had relayed “vague reports of a taboo no-go area” around the BrayTech station.⁸

With the assistance of Variks and the Guardian, a number of Eliksni fled Europa to join Mithrax’s House Light.⁹ Variks expressed some doubt about Mithrax’s age and ability to lead, as well as the small size of his house.⁹¹⁰ However, he still saw Mithrax as a symbol of hope for the Eliksni.¹¹

In the past, Mithrax has been in contact with at least one of the Spider’s associates.¹²