the virus inadvertently transfers into Sigma. While the virus is purged from Zero, turning him benevolent, the virus adapts to Sigma, becoming the Sigma Virus. After gradually succumbing to the virus, he suddenly leads a mass revolt among the Reploids, declaring total war on humans. Many Maverick Hunters follow Sigma out of loyalty, leaving Zero in charge of the organization. X, the last creation of Dr. Light and the base model for every Reploid decides to volunteer and joins Zero. X and Zero battle through the Maverick regime, and it is X who finally destroys Sigma. But though his physical body is scrapped, Sigma's "soul" (the Virus) survives. After the end credits roll, Sigma's face appears on a blue monitor and warns X that he will be back. Sigma returns in each installment of the series in various forms but is defeated by X each time. His final appearance is in Mega Man X8 - although he is finally destroyed for good, the Sigma Virus remains, prompting the events of the Mega Man Zero series. Other games Sigma appears in the crossover game Marvel vs. Capcom Infinite. In the story mode, he merges with Ultron to become "Ultron Sigma" to convert the inhabitants of both of their worlds into their slaves. Sigma as a playable character is available for purchase as standalone downloadable content or as part of the game's character pass. Cartoons and anime Though not a starring character, Sigma was referred to in an episode of the 1994 Mega Man cartoon, where X, Vile, and Spark Mandrill go back in time. His profile, shown by X, mistakenly spells his name as Cigma. The only lines Sigma has is when Vile contacts him near the end of the episode. He also appears in a short unlockable OVA in Mega Man Maverick Hunter X entitled "The Day of Σ". It shows the Maverick Hunters prior to the events of the first Mega Man X game under Sigma's command, before he ultimately revolts. Development Mega Man X was originally meant to have a team of three villains, one tall, one short, and one chubby. However, the designs by Keiji Inafune were merged to create a single villain, Sigma. These designs were later reused as the basis for Mega Man X2's X-Hunters. Ever since his creation, Inafune aimed parts to his appearance to hint a connection with Mega Man villain Dr. Wily.