Here we have Sigma's original incarnation from Mega Man X.  His stylish cape gives him a regal bearing (even if the steel shoulder pads betray something of a 1980s fashion sense).  You can even catch a glimpse of his trusty lightsaber peeking from behind the cape.  Of all of Sigma's redesigns (and there have been many), this look still remains my absolute favorite.  It tells you everything that you need to know about the character at a glance and is much more memorable than anything that followed.

Sigma sports knuckle claws for some Wolverine action and they're on full display here in this design from Mega Man X2.  Sigma's physical forms tend to grow in size from one game to the next as he seeks out better battle bodies, and frankly I've always felt that the designs become much too complicated to properly appreciate.  Sigma's look becomes just downright busy in later games and we can see the beginning of that trend here with the extra emphasis on his feet, legs, and shoulders.  The proportions seem off to me, but since Sigma is a robot Reploid, I suppose his actual shape is entirely up for grabs.  The sigma symbol as a belt buckle of sorts is a nice touch though.

Sigma's return in Mega Man X3 tosses the cape in favor of a series of spider-like legs mounted to his back.  The sharp claws have been replaced with spiked wristbands from his original design to match the spiked belt.  His feet are still crazily oversized compared to the rest of his body, but at least the shoulder pads remain in spirit.  Curiously, his chin seems to be evolving into a shape not seen since Jay Leno became famous.

Sigma isn't one to reuse a physical form if he can help it, and his appearance in Mega Man X4 is meant to invoke imagery associated with the classic Grim Reaper figure.  Note the cape (shredded this time to represent Sigma's many defeats) and the energy scythe weapon.  Purple and yellow are the themes here, his feet are still huge, and those shoulder pads are larger than ever.  His head almost gets lost in all of the visual busyness happening here.

This is Sigma at his most simplistic from Mega Man X5.  Clad in black and white with more realistic proportions, I might almost expect him to be a regular playable character in this incarnation.  There's not much to him here.  The purple streaks represent a cast-off cape and shoulder pad accessory, and his muscular build makes him look almost human. 

Sigma was on his way out by the time Mega Man X6 debuted, and while he would continue to play a part in the upcoming sequels, his role was diminished.  Here he shows up as a broken wreck bent on revenge (as noted by the tattered cape) almost as an afterthought.  He has no flashy weapons to show off in his artwork this time.  He's broken and beaten, but just as mad as ever.   

Capcom did not produce any official character promotional art of Sigma for Mega Man X7,  but Sigma's place in Mega Man X8 features him manipulating events from behind the scenes once again, and this partial look his latest form combines several elements from his previous forms.  Take notice of the lightsaber hanging from his waist, for instance, as well as the clashing green, red, and purple colors that make up this design.  The shoulder pads are integrated into his shoulders this time, and the high collar gives the impression that his seemingly indestructible head had just been bolted to the body.  Are you ready for the surprising reveal?  This isn't the real Sigma.  It's actually a Reploid using a copy chip to impersonate him.  No wonder the design draws from previous Sigma concepts.

Sigma's final form in the main X timeline throws away just about every familiar aspect of his design.  Mega Man X8's take on the real character adds horns, does away with the shoulder pads, and looks completely different than anything that's come before.  Only the general head shape is the same, as is the crystal embedded in Sigma's forehead (though it is green now instead of red).

While ultimately canceled, this was to be Sigma's appearance in Rockman Online.  It's a return to a classic look and an updated concept on the one appearance that works best for the character.  The cape and shoulder pads are in full effect as are the spiked wristbands.  This may well be the definitive Sigma design.  Such a shame it did not have an opportunity to be properly showcased.  Sigma has changed so much over the years into so many bizarre and outlandish forms that seeing him depicted in his classic incarnation feels refreshing.  It's as if this is the way he's meant to be.  It's certainly how I'll remember him.

(Special thanks to David Oxford and The Mega Man Network)