Little is known about Sleeper's personality, as he was for the most part dormant. During Gold Morning, he was willing to use his power on refugees at the Zayin settlements. Some time later, Khepri found Sleeper sitting and reading a book out loud to himself.
When Legend deterred Sleeper from emerging some time after the Attack on Teacher, Tattletale believed he was only dormant for now. If Sleeper had motivations for making one attempt, she believed he would budge again soon.
It is possible to bait in Sleeper and lure him to a location.
From an out-of-universe perspective, relatively little is known about his power. However, Sleeper deserves his reputation: he does not have a Stranger power to be inherently viewed as a dangerous S-Class threat. During Gold Morning, Khepri declines to capture him while collecting parahumans to use against Scion, believing him to be "more trouble than he was worth".
His power manifests as a 'storm' that from a distance crackled, boiled, and popped. The storm looks like a cloud of rainbow shimmers; according to Defiant, the rainbow sheen somehow felt nonsensical with the way the colors unfolded. Sleeper's storm appears to move relatively slowly; it crept forward at the horizon when the Wardens lured Sleeper to the City.Defiant describes the storm as being Sleeper: this could possibly imply Sleeper has a Breaker power where the awake state is the storm and the dormant state is humanoid. The storm was large enough to hang over one part of the City while Sleeper was present in the area.
During Gold Morning, Sleeper went through the Zayin portal while refugees were still setting up the settlements at Earth Zayin and the storm swept over them. Although Sleeper's storm did not cover a large area, it still swelled in size to be large enough to encapsulate the portal, every nearby settlement, and most of its fleeing inhabitants. The storm disrupts communications in the affected area; by settling near the portal, he blocked the refugees who escaped the area from getting back via the portal.
When the Simurgh was flung into Sleeper's storm, she was trapped, lay prone, and was taken out of the picture entirely. She was still dealt with even after he retreated from the area. Wildbow mentioned the following hypothetical capes would be 'goners' against Sleeper:
A cape that can transform into a lightning-like state, who can cause damage in this state by firing lightning bolts.
A cape that can absorb her own body volume of any inanimate matter more durable than herself to temporarily take on its properties (except for appearance and mass), permanently destroying whatever she consumes.
A cape that can sense and understand the emotions of others involuntarily.
The Wardens had specific countermeasures in mind and looked for capes with any of the following to go up against Sleeper:
Torso could counter and defeat Sleeper, given the ability to reach him. When Sleeper started to emerge at one point after the Attack on Teacher, Legend leveled around 30 km2 of city in an unknown timeframe to cause him to go dormant again. Wildbow noted that a hypothetical Shaker that can transform the atoms of any solid within 200 meters into a crystal-like organization, slowly spread the crystal effect through connected solids, and is Manton limited against herself and biological matter would have a very slim chance of surviving against Sleeper.
Based on the countermeasures and capes effective against Sleeper, some speculations can be made. The storm likely appears to be capable of devastating anyone inside unless they have All-or-Nothing defense, can physically keep taking on different forms, or have a special enough brain. His power might be fueled by some forms of matter or is related to some form of matter subversion/creation, as Legend leveling areas of city could deter Sleeper and the hypothetical Shaker had a very slim chance of survival. Destructive attacks that are All-or-Nothing are likely effective against the storm itself.
Dragon and by extension Saint continue to monitor Sleeper's activity, though they consider him a secondary threat because he appears to be dormant. Saint noted that Sleeper shifting fractionally wasn't rare.
The Mordovia Bubble was hit at the beginning of Scion's rampage, rousing Sleeper. He then traveled to Earth Zayin by portal and effectively cut it out from the greater humanity by settling near the portal and submerging nearby settlements in his power.
Using the Clairvoyant, Khepri found Sleeper reading and sitting on a lawn chair on a balcony in Earth Zayin. Deeming him too troublesome to collect, she let him be.
The Wardens confirmed Sleeper was active and moving, though not fast enough to matter right now and thus ranked a non-immediate threat.Legend was able to dissuade him from approaching by scorching out no man's land.
The Wardens baited in Sleeper and lured him to the City specifically to slow down the Titans. It had little effect by itself, but following the intervention from Titan Fortuna, Sleeper's storm was able to trap and take out the Simurgh. Following that, Sleeper retreats and returns to passivity.
Wildbow has stated that Sleeper was included in Worm as a result of a fan's comment that not every character should be fully explained.
In the parahumans list, under Sleeper's power, Wildbow had a message with a caesar shift of 5, saying "As if I'd really put something here. For real."
Sleeper's name seems to be a reference to "let sleeping dogs lie" proverb, whose equivalent also uses the same sleep-metaphor in Russian language too, except with a specific evil bogeyman in place of dogs. "Не буди лихо пока оно тихо" or if literally translated into English: "Do not wake the Evil while it is quiet"
↑ 1.01.11.21.188.8.131.52The Simurgh lay prone within the storm that was the Sleeper. Unmoving. That hadn’t been him. That had been Dauntless, acting with the benefit of Titan Fortuna’s sight, guiding the direction of the blast.
The storm crackled, boiled, popped, the colors taking on a rainbow sheen that somehow felt it shouldn’t make sense with the way the colors unfolded.
↑ 2.02.12.22.32.42.5When everyone at the Zayin settlements had still been getting set up, that same cloud had swept over them. Nobody had been able to get a message to them to warn them. They’d fled, but communication had been all over the place, a few people had been left behind, most of the others hadn’t fled far enough. The storm had swelled in size, and it had encapsulated every settlement in Zayin. It hadn’t been a large area, but it had still been mostly everyone, and it had included the portal the rest needed to get back.
↑ 3.03.13.2He shifted his foot, and once again, the screens changed their focus, the rest of the data shifting to miniature windows and moving to the periphery of the viewing area. The focus at the center was on the class-S threats. The Endbringers were stable, all in a resting state.
Secondary focuses. Not the kind of targets that Dragon checked on with any regularity. [...] Sleeper was, as far as anyone could identify anything about the threat, dormant. [...] The secondary threats… quarantine still unbroken. Sleeper had shifted fractionally, but that wasn’t so rare. - 26.x (Donation Interlude; Saint)
↑ 4.04.14.24.34.44.5Sleeper. I could see him, sitting on a lawn chair on a balcony, reading a book out loud to himself.
More trouble than he was worth. I let him be. - Speck 30.4
“Restless but still around. Earth Zayin in the palm of his hand. He started to emerge, Legend faced him down.”
“Leveled about thirty square kilometers of city.”
I nodded. “He’s dormant now?”
“For now. If he had motivations for making one attempt, he’s going to budge again soon. But I don’t have the instinct he’s our threat. He’s background. Someone else’s problem.” - Excerpt from Sundown 17.9
↑ 6.06.16.2“I am fucking open to better ideas, anything,” I told her. “But I’m worried the Wardens’ contingency plans won’t work-”
“Sleeper has been baited in. No luck. Saint had a trick up his sleeve when it came to dealing with A.I., in case his big red button for dealing with Dragon didn’t work. He’s trying it on the machine army.” - Last 20.9
↑ 7.07.17.27.37.4“First of all, the Sleeper is retreating. He is not an immediate danger, and we will let you know as soon as we can, if that changes.” [...] “The Sleeper was lured to the city specifically to slow down the Titans and was used to trap the Simurgh. Some of our best minds and strategists are confident the Simurgh is dealt with.” [...] “Didn’t you want to be a lawyer?” Presley asked, leaning onto the snow-dusted railing. In the distance, Sleeper’s cloud was receding. - Excerpt from Last 20.b
↑“Didn’t need doing in the first place,” Triumph said, sighing. “I was prepared to risk my life the day I graduated from the Wards. Knew what I’d be getting into. Week I had clearance, I watched all the video we have of the class S threats. Leviathan, Simurgh, Behemoth, Slaughterhouse Nine, Nilbog, Sleeper. I knew what I was getting into. So I’m not shocked or horrified at the attempt on my life. What gets me is what you did to my dad. Set his career back years, if it’s even recoverable, by forcing him to take that stance. The whole thing, start to finish, was unnecessary.” - Queen 18.4
↑Wildbow: Same sort of thing the Vegas capes were doing.
Dealing with the class-S threats that aren't so obvious as Sleeper, Nilbog or the Blasphemies, and the villains who don't take the spotlight. - Comment by Wildbow, archived on Spacebattles
↑“No,” the Number Man said, and he managed to sound only a little condescending. “I’m saying that parahumans as a whole are chain reactions waiting to happen, and we were already approaching a critical point. Every year, the percentage of parahumans in the population increases. At that same time, the odds of a cataclysmic event happening somewhere are increasing steadily. Imagine a situation like the Echidna event that turned out more unfavorably, or a Nilbog who wasn’t content to stay in one place. We have the blasphemies, Sleeper, and the Ash Beast, even the Slaughterhouse Nine, all as living examples of this concept at work. The world already stood on a precipice, and I’m not even mentioning the Endbringers in all of this.” - Extinction 27.2
↑But it would let us do something, when we were faced with a series of situations that felt hopeless. Fucking Sleeper. The Machine Army. - Excerpt from From Within 16.2
↑ 12.012.1“Not taking over, and not doing what they did,” I said. “They’re- you’re, if you want, you’re still a fixture. But the Wardens were always focused on the top-level threats. Distant wars. Class-S stuff.”
“Ogun,” Weld said. “Sleeper. Machine Army. And a bunch of other things I can’t even namedrop, because they’re classified.” - Beacon 8.2
↑“Because I can’t shake the notion that this isn’t about Amy Dallon, it isn’t about Dauntless, it isn’t about the Machine Army, Pastor, Nilbog and the goblins, Sleeper, the Blasphemies, Teacher, or any of the other major threats we’ve been keeping an eye on.” - Sundown 17.10
↑ 14.014.1"Wildbow: Sleeper was written in as a response to a fan saying that I shouldn’t go into detail and explain every character. He featured in a snippet I wrote back in the day (I spent ten years writing bits and pieces of superhero stuff before settling on the story I wanted to write) and seemed like a good one to drop in. He does have a power, but I think it’s best left unsaid, perhaps until the sequel." - Interview with Wildbow by t4nky
↑Yamakaky: A fan theory is that it power is to be viewed as a dangerous class S threat.
Wildbow: I've said this isn't it several times now. - Wildbow on Reddit, archived on Spacebattles
↑ 16.016.1It was her first good view of it, and it kept getting more intense, but what had drawn their attention and brought everyone to the rooftop was the cloud of rainbow shimmers that hung over one part of the city. She’d heard about what it was, she’d seen pictures. She’d heard about what it was, she’d seen pictures. - Excerpt from Last 20.b
↑Sleeper’s storm was creeping forward. [...] Sleeper was at the horizon, south of the Simurgh and Titan Fortuna’s small army of Titans. - Excerpt from Interlude 20.a II
↑ 18.018.118.2I nodded, but I was distracted from my response by another vibration of my phone. I picked it up to look at it.
Mordovia bubble hit. Sleeper has been roused, last tracked en route to Zayin portal. Casualties unknown. - Extinction 27.3
↑The largest settlements that remained, the most obvious targets. There was one in Zayin, but the Sleeper had followed the refugees in there. Even if it still stood after Scion's visit, there was no helping any of the refugees there. - Venom 29.9
↑The Simurgh was out of action. Sleeper had her. - Last 20.10
↑NamedByAFish: Can transform your body into a "lightning" state, from which you also have a blaster power of -- you guessed it -- lightning bolts. Strong, but it acts like real electricity and tends to make both your lighting bolts and yourself follow a path of least resistance. Your lightning-like state is immune to damage, but can only cause damage via lightning bolts. You can also move nearly as fast as real electricity in your lightning state, but again find it hard to deviate from the path of least resistance. [...] Wildbow:
↑NamedByAFish: Can absorb her own body volume of any inanimate matter more durable than herself to take on all properties of the material aside from appearance and mass. This also grants her the necessary strength to move her body volume of the material as easily as she would normally move something weighing the same as herself. Using her ability permanently destroys whatever she consumes, but the effect to her only lasts for five minutes per "charge." She can "recharge" by any amount whenever she has access to the material she used for the original charge, but if she wants to change to using a different material, she has to use something more durable than whatever material she is currently mimicking. Synergizes well with your power if she chooses a conductive material. Causes property damage whenever she uses it for obvious reasons. [...] Wildbow:
↑A bit of a "fourth wheel" to your synergizing trio. He senses and understands the emotions of others involuntarily. If he focuses, he can see why they feel that way, giving him a constrained but powerful retrocognitive ability. Adept at using this knowledge to his advantage during negotiations. [...] Wildbow:
↑Naphtha was striding down the hallway, coming in our direction. He stopped us. “Changers?”
“No changers in our team,” Tristan said. “Why?”
Naphtha getting close enough meant I felt the oil touch my skin, as it touched everything in a certain radius of Naphtha. He pulled it away from me as it touched me, but my skin crawled with the memory of the feel of it.
“Another crisis. Similar to the others. Going to announce it to the dining hall,” Naphtha explained. “I don’t suppose any of you feel brave enough to go up against Sleeper? Absolute invulnerability better than Alexandria’s, special brains, absolute annihilation powers?” - Excerpt from From Within 16.2
↑museofdoom2: Torso is metal as fuck. He is a truly top TIER cape, drop him over Sleeper and there will be no more Sleeper anymore :). I fucking love his character already. Weird, crazy ass OP power and his personality is pretty cool too.
Wildbow: You might be right. I was just thinking about it. - Wildbow on Reddit
↑Can transform the atoms of any solid matter within 200 meters into a crystal-like organization. Chemically, this substance straddles the line between covalent crystal and metallic crystal: it is nearly as durable as carbon crystals (diamond and graphite) and is chemically inert, but has an extremely high melting point and is an excellent conductor of heat and electricity. This crystal effect slowly spreads through any connected solids after three seconds of sustained contact with an affected surface. Synergizes very well with her sister's ability and yours, as this arrangement of atoms is both extremely durable and a good conductor. Manton limited against herself and any other biological matter. [...] Wildbow:
↑It wasn’t Jeanne who answered. Cinereal gave me my reply. “Thinkers say no. They’re either drawing blanks or they don’t like what they see.”
“Nothing specific? No details?”
“No,” Cinereal said. “But if you look at some of the other major thinker blind spots, you’re going to find yourself running into topics like Eidolon, Sleeper, the Endbringers, Valkyrie, the Island-state, the Pastor incident…”
“Concentrations of power,” I said.
Jeanne shook her head. “Complexity of power, most often. Whatever thinker powers come into play, with these cases, there’s often too many variables to fully consider, thinkers report that their powers are fuzzy, inconsistent, or blacked out.” - Blinding 11.4
↑Not as I or my power understand circumstances, and my power understands everything outside of the blind spots that are Teacher, Valkyrie, the Simurgh, and two broken triggers that authorities aren’t aware happened.” - Dying 15.7
↑► Ferris (Cape Dad) Replied on August 22nd, Y1: Right now we don’t seem to have many threats at home. Things are quiet. The monsters are out there if they’re even alive. Sleeper is still in Zayin and seems contained there. - Glow-worm P.6
↑“Sleeper is still parked in Zayin. I wanted to tell Gary Nieves that Cauldron capes are stable. We have the power and we’re not as driven toward violence and drama. We’re safe.” - Interlude 5x II
“I warned people to be wary. All hero teams should be standing down, villains are holding off until a meeting tonight.” - Polarize 10.11
↑Villains had assembled in Sherwood Span. The area was sparse, spread out. Some buildings were in construction, but it looked like that had stopped. Mostly it was scattered houses.
The major players were notably absent, though Tattletale was keeping an eye on the spies.
A disorganized mob consisting of two- and three-person gangs, solo operators, mercenaries, the blacklisters that fought over internet rankings, the burglars, kidnappers, the enforcers and killers. A handful were notable in their own way, like Little Midas. - Interlude 10.x II
↑There were other things. News. Status of Class-S threats…
Machine Army; 4.83% growth since last check, active
Endbringers; one dormant, one active, others dead or unknown locations.
Active Endbringer. She zeroed in on that. A few mouse clicks brought her to a site that tracked the Simurgh. - Interlude 10.x II
↑“Ha, no,” Tristan said, genuinely amused. Then his face fell, “Wait, is he moving?”
“Yeah. But not fast enough to matter right now. It’s another thing demanding attention, focus, and manpower.” - Excerpt from From Within 16.2