From Destinypedia, the Destiny wiki
Valus Thuun is a Red Legion commander that is the main boss for the Tree of Probabilities Strike, having ventured into the Infinite Forest in hopes of finding a simulated future that they won the Red War. In their failed expedition, however, Thuun and his forces became trapped in a combat loop that continuously pitted the Cabal against the Vex while trying to steal the map to the Forest itself. When the Guardian and Sagira arrive to secure the map and find Panoptes, Infinite Mind, the Vex diverted the Red Legion into halting their progress whilst Thuun destroyed the map. It was to little avail as the Valus met his final fate, dooming him to a cycle of endless death upon repeat of the combat loop.
Since the death of Panoptes, a glitch in the simulation that trapped Thuun and his forces began to fracture them into copies that threaten to overwhelm and even escape the Infinite Forest. Sensing the temporal anomaly occurring within the network, Ikora, Osiris, and Sagira provided tactical support to the Guardian Strike teams to destroy the simulations of Thuun for good.
Thuun primarily attacks with a specialized Cabal weapons platform with two different modes of fire. The primary fire mode acts like an enhanced Slug Rifle, with a faster fire rate and higher impact, albeit each shot travels in a slight arc; the secondary fire mode is the unique Concussion Rifle, which fires a barrage of Arc blasts which can knock Guardians back a significant distance. For melee combat, Thuun will smash his fist into the ground, releasing a shockwave that will pound a Guardian's shield and send them flying in the opposite direction, and occasionally, he will close the gap by using his jetpack to thrust him forward, causing him to smash the ground again. One must be particularly wary of Thuun's Concussion Rifle, as it can potentially force The Guardian away from the fighting space altogether with little effort, so constant movement is advised.
List of appearances