Primus Ta'aun was the leader of the Sky Burner Legion stationed on Phobos. After Primus Ta'aun rammed the Sky Burner ship Dantalion Exodus VI into Oryx's Dreadnaught after the Sky Burners base was destroyed, Ta'aun led an attack to seize a Hive portal and was Taken by Oryx in the mission Enemy of My Enemy. He would later return by the name "Tau'un, Hand of Oryx" and fight the Guardian along side Baxx in the mission Regicide. Tau'un's death enraged his two brothers and former bodyguards Valus Mau'ual and Valus Tlu'urn. In an act of revenge, they led a strike team to the Dreadnaught's core to blow up the Hive Ship. This led to the events of the strike Shield Brothers.