Isoc

From MMKB

Isoc is an enigmatic character from Mega Man X6. He first appears after the intro stage, warning the populace of the threat of the Zero Nightmare, and encouraging Reploids to join in the cause to obliterate the new virus. In reality, however, Isoc is actually working as a subordinate of Gate, the scientist responsible for the Nightmares.

Like Serges in Megman X2, there is a prominent theory that Isoc is a robotic form of  Dr. Wily.  This is made evident in the video sequence after Zero defeats High Max. Isoc watches Zero destroy High Max, laughing uncontrollably. When Zero asks why he is laughing, Isoc responds that he cannot help it after seeing how powerful Zero has become, pointing out that while X could not defeat High Max, Zero has done so easily. Zero then tries to attack Isoc, when Isoc raises his hand, generating a force field that immobilizes Zero. Alia notes that Isoc would have to have a detailed understanding of Zero's design in order to create such a field. Isoc is not seen again until a video sequence after X defeats Gate, when X finds Isoc's body on the ground. Alia informs him that although Isoc's body is still functional, his DNA signature is gone, leaving him an empty shell, similar to the Erasure incident in Megman Xtreme 2. She asks X to take a closer look at the body, but X doesn't have time, as he has to go after Sigma.

Sigma revealed in Megaman X5 that Dr. Wily was still alive in some form, and both Isoc and Serges look physically similar to Dr. Wily and are shown to understand Zero's design and body. It is possible that both reploids were in fact Dr. Wily, working towards his plan to turn Zero into a Maverick.