The fusion mortar is a weapon that can only be used by the juggernaut. It launches large arcing projectiles that emit green smoke and make loud noise. Like the grenade launcher, the mortar launcher's projectiles arc, however, they take more time to arm and are heavier.
The fusion mortar is perhaps the most destructive weapon in the game (with the missile launcher). Its large explosions kill most small assets and scouts who are too late to run in one blast. However, the Juggernaut may only carry ten rounds, which are depleted easily when destroying the enemy base and fighting off those who are chasing him at the same time.
Usage
Targeting Laser/Mortar Combination
Heavies who are trying to hit turrets, sensors, and vehicles from afar may find it hard to hit their targets, which is why the Targeting laser/Mortar combination is so deadly. If a teammate targets an enemy asset for a heavy, the heavy knows exactly where to place his reticle to fire and hit the enemy asset with precision. This makes it so the enemy team has to come and distract the targeter/heavy in order to get them to stop.
Hit and Run
A very popular tactic for juggernauts and mortar launcher is the hit and run technique. Most heavies, if the terrain permits (such as it does on Katabatic and others maps that allow heavies to pick up speed with hills), can ski into the enemy base and destroy it before anyone can react. If the juggernaut is unable to camp inside the enemy base, he will usually end with a Suicide Mortar.
Suicide Mortar
Most heavies, when they are about to die, end by shooting a mortar at their feet. This usually kills the heavy, along with any shocklancers who were trying to kill the heavy.