Marvin The Martian is the superior ruler of Mars. He's an inventive genius and plots to destory the earth
In "War of The Villains", Marvin went aboard Invader ZIM's newest weapon, and kindly requested for him to seize trying to take over the planet earth. However, ZIM stated he had no time for reasoning, and and that NO ONE takes his mission away from him. Angered, Marvin fired one his lasers at the key weak spot of ZIM's weapon (The Self-Destruct Button OF DOOM!) and left ZIM to perish as he retreated back to Mars.
After the series was revisited on The DvND forums, Marvin later fought Vexus. Marvin offered an alliance with Vexus, who refused due to Marvin's Size and Appearance. Insulted by Vexus' hurtful comments toward him, he took out two laser guns and shot rapidly at Vexus, who deflected every shot. After Marvin was out of ammo and Vexus insulted his attempt, Marvin informed he has "spent every moment since graduation plotting to destory the earth". Vexus though this factor was a mere joke, which infuriated Marvin.
Later, Marvin would attempt to blow up Cluster Prime. Vexus thought this was just a plea for attention in order to make her change her mind for the alliance, but Marvin later informed her that he can take over the world without her assistance, and blew up Cluster Prime.
Kylo Ren tells Marvin, Gallaxhar, Captain Smek and Gantu to invade the Beast's castle but Sir Rupert defeated him. He reforms and joins the Great Alliance