Mars is an extraterrestrial Robot Master found, activated, and used by Dr. Wily. He was first seen in Mega Man V as one of the games 8 Robot Master Stardroids. Like Napalm Man, Mars is a virtual walking arsenal - in addition to his signature weapon, the Photon Missile, he has a large battery of shoulder-launched missiles, an autocannon, and a pair of bomb launchers in his arms (which do prevent him from using planes for his travels, though). Mars is also mounted on tank treads, like his predecessor from Mega Man 5. Mars is armed and armored to the teeth, and is widely regarded as the hardest Stardroid.
Despite his warlike appearance, Mars is very compassionate to his friends.
Mars has 3 different attacks: He can jump in the air and launch a massive barrage of rockets, stand in place and continuously fire his autocannon, or launch a volley of 3 photon missiles (these will stay in place for a brief second but move much faster and are deadlier that Mars' other rockets). The autocannon bullets can be shot down with the Mega Buster, but both types of missiles are hard to dodge as there are either a lot of them or they possess homing capability. Mars' weakness is Salt Water, and it is highly recommended to take out Neptune before killing Mars. Salt Water will not absorb a projectile if the two connect, so the player must still dodge attacks.