Copy Sigma

Copy Sigma appears in Mega Man X8 as the boss of the Gateway stage. Although he looks and acts like the true Sigma, he is in fact a New Generation Reploid (a Guardroid) copying his form. Other Guardroids also takes this form in the Sigma Palace, appearing as a stage enemy named Guardroid σ.

Characteristics
Copy Sigma physically resembles a sleeker, modern version of Sigma's original body. He has a tall, muscular purple body covered by a green chestplate with a round orange crystal, a tall red collar and silver shoulder plates. He also wears brown boots and red gauntlets. The facial scars have become lines running across his entire head, and his eyeballs are black with glowing, empty irises. He has a beam saber attached to the left side of a red belt.

The Copy Sigma that appears as a boss is much stronger than the stage enemies from Sigma Palace. It is said in a strategy guide that only 1 in 10,000 New Generation Reploids is at the level of the Gateway boss.

Only the boss of the Gateway stage interacts with the player character. He speaks as though he is Sigma himself by "allowing" the Maverick Hunters to call him by that name. Despite not being Sigma himself, the New Generation Reploid appears to embody Sigma's essence, displaying the same personality traits. He does not speak in the same personal level as the true Sigma, however.

Mega Man X8
With the advent of the Jakob Project, a line of New Generation Reploids based on Axl are produced to colonize the moon. However, the project is taken over by Sigma, who inserts his DNA data on their Copy Chips, essentially making them "become Sigma". Sigma then starts an uprising with the New Generation taking over the moon, with the first CopySigma challenging the Maverick Hunters in the Gateway. When the Maverick Hunters reach the moon, the Sigma Palace is defended by a large number of Reploids copying Sigma's form, but they fail to stop the Hunters.

Trivia

 * The name "Copy Sigma" was coined by the Rockman X8 Original Soundtrack.
 * Mega Man X8 designer Tatsuya Yoshikawa based Copy Sigma's design on the "plain yet powerful image of Sigma from Mega Man X, putting special attention in defining a final look for Sigma's chin.
 * Although Copy Chip production is resumed years after being cancelled due to the Jakob incident, it is unknown if the new Copy Chips still have Sigma's DNA.
 * Copy Sigma marks the second time X and Zero have faced a copy of Sigma, the first being Sigma Limited.
 * Copy Sigma's fighting style is similar to the first phase fights against Sigma in Mega Man X/Mega Man: Maverick Hunter X, and to a lesser extent Mega Man X5.