Comfortable with his leadership role as head of the Brockton Bay Wards, the PRT intended to test this leadership by having him swap with Weld from Boston. Recognized as capable and intelligent by the criminal elements in the city. Like all teenagers he had something to prove which would come back to bite him.
Carlos is described as a young man of Puerto Rican descent who wore his hair long.
He wears a rust-red costume with a matching helmet, both with silver-white trim, and a shield emblem. His costume left some of his skin exposed and his eyes visible. During his first appearance, however, he switched costumes with Clockblocker as part of a plan to trick the Undersiders.
He carried a variety of grenades (flashbang, tear gas, incendiary etc.)
Aegis possesses the ability of flight and an augmented physiology that operates at peak capacity as long as he is still living.His entire biology is filled with so many redundancies and reinforcements that it makes it very difficult to put him down. For example: blinding him allows him to see by sensing light through his skin, cutting his throat bleeds no more than cutting the back of his hand, cutting off an arm would only last until he could get it reattached and stabbing him in the heart means that other organs would take its place. Aegis could survive decapitation.
During the Wards' confrontation of the Undersiders at the bank, Aegis survived being slammed into the ground hard enough to kill an ordinary person and stood back up after less than a second. Angelica held him in her mouth and whipped him around like a toy, but he kept fighting. After Brutus and Angelica played a game of tug of war with his body, Kid Win hit them with a series of bolts from his Alternator Cannon, blasting the three of them into the opposite building. It took the dogs some time to get up, but Aegis was in the air immediately. 
Aegis' augmented physiology allows him to abuse his body in ways that make him appear to possess supernatural strength. He can throw punches hard enough that they’d break his hand, mangle his joints and tear his muscles, and his body will take it. He can further enhance his strength by undergoing adrenaline rushes that he can keep going for hours. This has the further side effect of making it so that he never gets tired. He was able to deliver a two-handed blow to Brutus' snout that knocked him over onto his side.
In addition to his flight and augmented physiology, Aegis does not seem to feel pain, although his powers allow him to deal with the drawbacks. It is left unclear if Aegis truly possessed a congenital insensitivity to pain (CIP) or if he simply had an incredible ability to simply "deal" with the sensation. Strictly speaking with his adaptive brute ability Aegis would be able to defeat Glory Girl.
Carlos likely Triggered between two and three years ago at age fifteen, and joined the Brockton Bay Wards team. Following Triumph's graduation into the Brockton Bay Protectorate, Aegis became the leader of the Wards.
During the battle at the Bank, Aegis led the Brockton Bay Wards to the bank after it was learned that the Undersiders were robbing it. He switched costumes with Clockblocker in an attempt to fool the Undersiders and have Clockblocker tag them, but this plan was foiled by Tattletale's power and he took a significant amount of damage from Hellhound's dogs. He later volunteered to be the last person Panacea healed, while debriefing the Wards.
Aegis spoke with a group of other Wards before Legend's speech and tried to defend other capes by tanking attacks during the fight itself.
When Leviathan was trapped, Aegis was assigned to an aerial route to prevent it from heading to the rooftops. He was killed when the Endbringer escaped. His body was so completely and utterly smashed that his powers could not do a thing to prevent his death. The damage was so absolute that no redundancy in his system could keep the resulting pulp alive, Clockblocker verified his death.
Brian shook his head, “Lisa, want to field this one?”
She did. “Aegis isn’t strong, but he can abuse his body in ways that makes it seem like he is. He can throw punches hard enough that they’d break his hand, mangle his joints and tear his muscles, and his body just takes it. He has no reason to hold back, and he doesn’t need to waste any time protecting himself from you. He can also draw on adrenaline… you’ve heard stories like how little old grandmothers lifted cars off the ground to save their grandkids?”
“That’s adrenaline at work, and Aegis can do that for hours at a stretch. His body doesn’t run out of steam, he doesn’t get tired, he doesn’t exhaust his reserves of adrenaline. He just keeps going.”
“So how do you stop him?” I asked.
“You don’t, really,” Brian said, “Best bet is to keep him occupied, keep him sufficiently distracted or stick him somewhere he can’t escape. Trap him in a dumpster and throw it in the river, you can get a few minutes of relief. Which is all harder than it sounds. He’s the team captain, and he isn’t stupid." - Excerpt from Agitation 3.3
↑Aegis probably lived (sheer dumb luck and the fact that he had something to prove in defending his home city that killed him in the first place), as did Gallant (who didn't go to Florida). - Excerpt from speculation by Wildbow on Reddit
↑Carlos returned from the shower, wearing sweatpants and a towel around his shoulders. He was Puerto Rican, his hair long. His body was clean of blood, barring a few residual trickles from the mess of ragged wounds on his arms, stomach and chest. He had clumsily stitched the cuts and gouges together, which did surprisingly little to make them easier to look at. He sat down on a chair and added his input for the lists, which didn’t amount to too much. He had been incapacitated for too much of the fight to have much to say. - Excerpt from Interlude 3
↑ 4.04.1Aegis, tan skinned, was wearing a rust red costume with a matching helmet, both with silver-white trim and a shield emblem. - excerpt from Agitation 3.8
↑Aegis – A young hero with a rust red and silver costume, with a shield emblem. Leads the Wards in his first appearance, has a biology filled with redundancies and safeguards, rendering him able to function no matter how damaged he is. - Cast (spoiler free)
↑Aegis [wearing Clockblocker's costume] didn't try to run this time. He stood his ground and reached for his utility belt. He retrieved something that looked like a miniature fire extinguisher.
Then he pulled the pin.
The explosion the flashbang grenade made was enough to leave me breathless, and there was a stone wall and some fifty or so feet between us. - Agitation 3.10
↑Aegis tosses a flashbang. Clockblocker covers his eyes and ears as best as he's able. [...] Yeah, once frozen, Duckblocker would be a sitting clock for any tear gas grenades, smoke grenades, or further flashbangs. If Aegis was feeling particularly violent, an actual incendiary grenade wouldn't be out of the question. - Wildbow on Reddit
↑Carlos Aegis Redundant biology, operating at peak capacity so long as alive, possessed of flight and ability to use body with no fear of self harm. Wards Brute Mover - Parahuman List; bolded edit by Wildbow
↑Aegis (Deceased) – Powers included flight and an augmented physiology that lacks any weak points. Onetime team leader of the local Wards team. Wore a rust and silver costume with a shield emblem. Perished in the Endbringer arc. - Cast Page (In-Depth)
↑ 10.010.110.2“Sure,” he said, “So let’s go down the list. Team leader: Aegis. You’d think he has the standard Alexandria package, flight, super strength, invincibility, but that isn’t exactly right. He does fly, but the other two powers work differently than you’d expect. See, he isn’t invincible… he just doesn’t have any weak points. His entire biology is filled with so many redundancies and reinforcements that you just can’t put him down. Throw sand in his eyes and he can still see by sensing the light on his skin. Cut his throat and it doesn’t bleed any more than the back of his hand would. The guy’s had an arm cut off and it was attached and working fine the next day. Stab him through the heart and another organ takes over the necessary functions.”
“Not that we’re stabbing anyone through the heart?” I made it a hopeful half-question, half-statement.
“No. Well, it wouldn’t be a bad idea to stab Aegis through the heart just to slow him down. If you did it with something big enough. The guy’s like a zombie, he gets back up within seconds of you beating him down, keeps coming at you until you’re too tired to fight back or you make a mistake.” - Excerpt from Agitation 3.3
↑ 11.011.111.2Aegis bolted the second the dog changed course, but it was too late. As he tried to fly out of reach, Judas leaped, nearly twice as far and high as I might have guessed something as big as he was could. The dog’s prehensile tail wrapped around Aegis’ torso. As they all fell, mount, rider and ensnared captive, Bitch shouted something I couldn’t hear, and Judas whipped Aegis straight down, adding the force of the throw to the momentum of the fall.
I thought I might have heard the impact from the interior of the bank. Or maybe it was as auditory illusion and my bugs were the ones who heard it. Either way, Aegis hit the ground hard enough to kill an ordinary person.
He wasn’t down for one second before he was on his feet again. In the same motion he used to get to his feet, he lunged for the dog and swung a fist at Judas’ snout.
Strong enough to slam a two ton dog to the side with one blow, chomped on by said dogs, whipped around like a chew toy, and continues to fight without slowing down. - Excerpt from Agitation 3.9
↑ 12.012.1He swiveled the cannon to face Judas, who was still guarding the spot where Bitch had fallen. A bolt of light erupted from the cannon and sent Judas flying beyond my field of vision. He fired another shot, at a greater distance, presumably at the fallen dog. Then he swiveled and fired off two more shots in quick succession, blasting Aegis and the two dogs that were gripping him.
The dogs and Aegis were all sent flying into the wall of the office building opposite the bank. While the dogs didn’t get up immediately, a bloody and tattered Aegis was on his feet in an instant, and in the air a moment later. He got to a good height – maybe two or three stories up, and stayed there, likely to get his bearings and survey the situation. - Excerpt from Agitation 3.10
↑While I’d been distracted by Clockblocker, Bitch had set Brutus and Angelica on Aegis. He was fending the two dogs off, but the white pane of his helm – Clockblocker’s helm – was shattered, now, and his costume was torn with one piece of ruined armor dangling by a string of cloth at his armpit.
Brutus lunged for Aegis, but as he passed over the edge of the area Vista had distorted, he fell short. The dog’s jaws clacked shut a foot away from Aegis’ face, spittle flying.
Aegis responded by slamming both fists, fingers interlaced, into Brutus’ snout. The dog crashed onto its side, giving Aegis the time to take flight once more, heading straight for the sky.
If I was surprised to see that display of acrobatics from one of the dogs, I doubted there were words for what Aegis’ must have felt, just then. Angelica seized the teen hero in her jaws and they plummeted together.
Angelica didn’t land with all four claws beneath her, and she sprawled as she hit the ground. When she stopped, though, she still had Aegis, one of his arms and half his torso clasped between her teeth. She whipped him around like a dog might shake a toy. When she paused, he was still fighting her, slamming his free hand against the side of her head over and over. Loops and strings of drool mixed with blood hung from her mouth. At least, that’s what I thought it was, from my vantage point inside the bank, peering through gloom and pouring rain. - Excerpt from Agitation 3.9
↑ 14.014.1AceOfSword: With his redundant biology he could have survived getting bissected I'm pretty sure. Aegis doesn't have any special protection against damage but most of the wounds he get turn out to be minor to him. Getting beheaded would probably only slow him down. It was pure bad luck that Aegis, who could have survived a lot of damage, got crushed into paste: even his redundant biology couldn't keep him alive when all of his body got wrecked.
Wildbow: Brutes (esp. regenerators) and changers often relocate their cores/coronas to the hardest to access part of their body, or adapt to do without. Crawler's wasn't in his brain, for example.
↑We got on the dogs, and Regent fired a salvo of shots from the laser cannon into Aegis, hammering him into the side of a building until the wall around him collapsed - Excerpt from Agitation 3.12
↑The problems with CIP (Congenital Insensitivity to Pain) don't tend to afflict someone with a natural ability to simply deal. Infection? Psh. Scratched corneas? He can see if his eyes get plucked out. Broken bones? Sections of muscle simply go rigid and offer the structure. - Reddit comment by Wildbow
↑Aegis is 17, very nearly 18, old for his grade level, he's already graduated high school and is taking prelim college courses (not the same courses as Faultline & Glory Girl). He triggered at 15. - Wildbow on Spacebattles
↑“Director Piggot. Ma’am,” Aegis greeted her, his voice strained. His costume was in shreds, and was more crimson with his own blood than it was its original white. It was bad enough his civilian identity might have been revealed, if it weren’t for the matted blood and the chunks of meat that had been taken out of him, some of the wounds nearly a foot across.
“Good god, Aegis,” her eyebrows raised a fraction, “You look like hell. What’s wrong with your voice?”
“Punctured lung, ma’am,” Aegis rasped, “I think there’s a hole in my front and back.” As if to demonstrate, he stuck his fingers into his chest cavity.
Director Piggot didn’t look away, but one of the men standing behind her looked a touch green around the gills, “I can take you at your word. You don’t need to stick your arm all the way through your chest to demonstrate.” - Excerpt from Interlude 3
↑New Wave’s fliers and Purity weren’t the only ones in the air. Aegis was also up there on the side of the good guys, but Purity had backup from Crusader and Rune. - Excerpt from Buzz 7.9
↑“Piggot has decided to take action in reflection of recent events. Both the Wards and the Protectorate are being restructured.”
Hannah winced, “How bad?”
Shrugging, Colin told her, “As far as the Wards go, we’re losing Aegis. Piggot and the PRT want to see how he does leading a different team, and the boy’s parents are amenable. He’ll stay in the Wards for a little longer, to suggest he’s younger than he is.”
↑Manpower deceased, CD-6. Aegis deceased, CD-6, my armband spoke, at the same moment my bugs reached the area around where Leviathan had been.
He was awake again.
Aegis would have been covering an aerial route, keeping Leviathan from heading to the rooftops, which meant Leviathan went up. I had the mass of roaches ascend, trying to get a sense of his location. I tried to use my armband to help gauge the direction he was traveling, but since I couldn’t move my arm, it was difficult at best. - Excerpt from Extermination 8.4
↑When Aegis was mashed to a literal pulp by Leviathan, to the point that he couldn’t function anymore, when he died, despite his power? I got to see the remains to verify for myself. - Excerpt from Queen 18.3
↑I spent a long time writing in this universe, and pretty much every character that shows up (or 95% of them) featured in the various snippets I wrote - I was struggling to write and rarely got past five pages, but it did a lot to help me wrap my head around the world and how it all fit together.
↑Mm, current plan is to have the Clockblocker/Vista bomb defusal incident take place onscreen via. an interlude, as I shuffle some around, delete some. Put a hero win front and center, give Aegis his interlude, and show more about strategy and the role the heroes take on the ground/with the public.
Not sure if I'll go ahead with it, it really depends on how it turns out in the writing/rewriting. Still, it's something I've been considering in light of Doc Mod's feedback and some other comments in this thread. - Comment by Wildbow on Sufficent Velocity