'Kusovai was known to fight practice duels with Rtas 'Vadumee. Later, he joined the group that boarded the Infinite Succor and realized that something was amiss. When they headed into a hunting preserve, Flood-infected animals began attacking the group. The group fought its way through to the ship's bridge, where they found the controls had been disabled.
'Kusovai was eventually infected by the Flood and fought the uninfected Rtas 'Vadumee. The Flood were almost able to make a Slipspace jump out of the system, but not before Rtas 'Vadumee changed the course so that the ship flew towards the sun. 'Vadumee, while fighting the infected 'Kusovai, was injured as an Energy Sword cut off his left mandibles. 'Vadumee defeated Kusovai and managed to escape two minutes before the Slipspace Jump occurred. Rtas 'Vadumee is believed to be the only survivor of the Infinite Succor mission, as all members of Rtas' team and the original crew of the craft, as well as the Legate on board, were presumably killed and absorbed by the Flood. If not, they were killed when the ship jumped into the system's sun.
'Kusovai's rank was Sub-Commander, and his armor color was shown in blueish-green, alongside Rtas 'Vadumee. It is most likely that he was only subordinate to 'Vadumee in his unit.
Unlike most Sangheili warriors, Kusovai's name does not possess the "-ee" suffix. Rather, his name bears the "-ai" suffix, which denotes swordsmanship. His case is similar to Toha 'Sumai's, who is also a master swordsman.
- Halo Graphic Novel (First appearance)