Why Sigma is My Favorite Megaman Villain

Megaman had some villains like Dr. Wily, Dr. Weil, Vile, etc. but for me, none of them stand out as much as Sigma. Sigma is the main villain of the Megaman X series (though he didn't appear in Command Mission, which may have confirmed his final demise). So what makes him all my favorite villain? Here's why I love to hate this guy, this sociopath villain of the Megaman franchise.

He's one incredibly shady big bad who is willing to do anything for supremacy, even sacrifice his own subordinates

He had been a shady dealer for most of Megaman, manipulating events throughout the series. In X1, he manipulated law and order to start his own army. In Megaman X2, he manipulated the X Hunters and even learned of Zero's origins (probably because he downloaded Zero's data during their first encounter). In Megaman X3, he manipulated Dr. Doppler into creating a new body. In Megaman X4, he manipulated the Repliforce into making him a super weapon he can use to destroy humanity. In Megaman X5, he releases the deadly Maverick Virus and manipulated Zero unknowingly. In Megaman X7, he manipulated the Red Guard and even Axl. In Megaman X8, he tries to control everything but gets destroyed by his own subordinate Lumine.

He doesn't know when to give up

From Megaman X1-X7, he just explodes and keeps returning. In Megaman X2 and X3, he was revealed to have become a computer virus. In Megaman X3, Dr. Doppler (or Zero) supposedly neutralized him but he managed to return in Megaman X4 as a shady dealer. In Megaman X5, he was supposedly aborted but Gate ended up resurrecting him in the process. I just love how Sigma is never easily taken down, no matter how hard Megaman X tries. At least, Lumine double-crossed him at the last minute to finally end his menace! Plus, he doesn't beg for mercy every time Megaman defeats him, most of the time he always promises to come back to make the hero's life really miserable!

His relationship with Zero 

Sigma was once the brave leader of the Maverick Hunters before he became the main antagonist of Megaman X. He met Dr. Wily's successor, Zero, and fought him. During that time, the Virus entered into his system and he began to embrace the warped path of darkness. He also tortured Zero constantly especially in Megaman X4 and X5. In Megaman X4, we realize that Zero was supposed to succeed Dr. Wily but Sigma took that place. In Megaman X5, somehow he got the data from Zero's programming, learned of Dr. Wily's existence from the Year 20XX and figuratively speaking, Dr. Wily became his new ally. He also caused the colony to crash hoping to awaken Zero from his current self, back to being what Dr. Wily intended Zero to be but UNDER HIS CONTROL. X4 was where Zero lost people important to him. X5, he tortures Zero in that whole game. 

An interesting backstory that seems to have many twists

There's the TV Tropes page that actually hints that the Sigma they are fighting may no longer be the real deal. Sigma was once the finest of Dr. Cain's creations before the latter rebelled. However, if one has played X2 to X3 - please analyze the form of the Sigma Virus. X2 has the Sigma Virus as the final boss. X3 has Dr. Doppler revealing to Megaman X that Sigma's true is that of a computer virus. Yet, his backstory in X4 shows that he was once the leader of the Maverick Hunters. So, how can that be reconciled? It seems that the real Sigma has been dead all along and that the Sigma Virus is the MAIN VILLAIN of the Megaman X series.

How does the Sigma Virus play through? In X2, Megaman X fought with Sigma after destroying the second body built by the X-Hunters. However, the Sigma Virus survived again and managed to return in X3 with a new body. In X4, Sigma managed to survive AGAIN. It seems that Gate does have a backup copy (but a poor one at it) for X6. So, it can be said that Commander Sigma is gone and all that's left is Sigma - the fan-favorite villain that makes the Megaman X so special. The Sigma Virus somehow has is very immune to anti-virus programs as evidenced by his survival in X3 and how he returned in X6. 

Plus Megaman X has to suffer much longer because of Sigma

Obviously, X suffers as the protagonist. Unlike Dr. Wily, Sigma knows how to torture the protagonist with various schemes. Megaman X got so traumatized resulting to his being a whiner in X7.