Kitun 'Arach is a Storm Covenant commander, taking charge of the faction after Jul 'Mdama's death. He is a major antagonist in Halo 5: Guardians.
Kitun and his brother Jacul both fought in the Human-Covenant War. After the war, Kitun was unwilling to make peace with humanity and ended up joining Jul 'Mdama's Storm Covenant. His brother, however, joined the Swords of Sanghelios and swore loyalty to Thel 'Vadam.
Kitun eventually became one of Jul's top lieutenants. He fought in the Battle of Kamchatka against the rogue Prometheans, forming a brief alliance with Fireteam Osiris to defeat them.
Kitun later left Kamchatka to go to Sanghelios to participate in the fight between the Storm Covenant and the Swords of Sanghelios. After Jul was killed by Fireteam Osiris, Kitun and several of Jul's other lieutenants took charge of the Storm Covenant.
During the Battle of Sunaion, Kitun found himself face-to-face with Jacul. The two brothers mortally wounded each other and perished.