Serges

Serges (サーゲス) is one of the X-Hunters of Mega Man X2. An integral part of the trio, it seems that he came up with the Unification and leads the plan with his vast intellect.

In the hidden rooms, he rides a platform and drops mines. He'll also jump in the air and send out shots in a circular motion. But hit him when he's on the platform (and when the shield is down) and he gets knocked down (it's really funny to watch). When you encounter him again in the second X-Hunter stage, he has this nasty machine that takes up the whole side of a screen, with platforms moving up and down. As well as that, the floor is layered with spikes, making this a difficult battle. The best bet is to use the Giga Attack to tear the machine open, and use either Silk Shot or Speed Burner for best results. Serges also reappears in Mega Man Xtreme. And he has the same vehicle he had in X2. His weakness to Speed Burner remains the same.

Dr. Wily?

It should be noted that there is a prominent theory that Serges from MMX2 is Dr. Wily. This is due partly to the Manga, which claims they are the same. (Non-Game sources generally create their own theories and ideas, and thus are not normally considered canon.) This comes from the fact that Serges states that the rebuilding of Zero is a Purification. Later in MMX5, Sigma tries to reveal Zero's true power with the virus by Purifying him. Serges has worked with Sigma, seemingly understood Sigma's body and Zero's. Serges built at least one body for Sigma, and possibly the bodies that show up in X4 and X5. The theory that Serges is Dr. Wily is usually shunned because Serges seems to be a minor character, and CAPCOM hasn't made him a bigger villain. Those that are for this theory simply claim he is, but was a minor character to keep the focus on the main characters, (I.E. Sigma, Zero, X) and build up a mystery. (Good for sales.)

And another theory claims that Agile, Violen and Serges are all Dr. Wily, just split amongst three minds.