Assault Soldiers are slower but stronger than regular Helghast troopers, and are reserved for major attack operations. They're trained in a wide range of Helghast small arms and explosive weapons, and know how to take advantage of emplaced guns. They can use a wide array of weapons on the battlefield.
They are much tougher than Elites but slow-moving due to their distinctive, thick armor, which makes them incredibly resilient to damage. They are also considerably more dangerous than assault soldiers thanks to their reliance on M327 Grenade Launchers.
In Killzone 2's campaign, Assault Troopers are as tough as can be because of their strong armor. They are divided into two sorts, Grenadiers and Commandos. They don't mind taking a beating, and often attack in packs, making them highly dangerous.
In Killzone 3, the Assault Soldiers are seen in a support role. They can be seen using missile launchers from elevated positions to support the assault infantry. In contrast to the invasion forces on Vekta, the Assault Soldiers on Helghan are restricted to the use of missile launchers, which raises the question whether the invasion force was better equipped than the homeland defense force. The lack of the grenade launcher in Killzone 3 also seems to have elliminated the Grenadier type of Assault Soldiers. The main strength of the Assault Soldiers in Killzone 3 lies in their numbers as they relentlessly attack in packs from elevated positions while hordes of infantry cover their flanks. However, two rounds between the eyes or the destruction of conveniently adjacent red/yellow barrels or petrusite canisters seems to be the panacea against them. But unlike their Killzone 2 counterparts, the Assault Soldiers of Killzone 3 wear more advanced helmets and goggles, which hints that it may contain a more sophisticated aiming reticule. This is supported by the fact that they presistently and very accurately aim for the player's head even if he is behind cover.