The Custodian is a parahuman made of air, invisible and almost completely incorporeal. She has the ability to create temporary duplicates of herself in enormous numbers, which she can either use for combat or to patrol Cauldron's base. She can manipulate objects with heavy or delicate force.
↑He withdrew a pen from his pocket, spun it around one finger. The notation billowed around it, and through it, he could see the movement of the pen, the plotted trajectory, the velocity and rotation of it. The numbers clicked into place with a speed that made the rest of him, his very perceptions, seem like slow motion.
Here and there, there were incongruities. Painting an entirely different picture. His companion was here, near him. Bending the most fundamental rules. The Custodian.
In another scenario, she would have been kept here and disposed of once we’d found a way to dissect her.
“I know you want to help,” he commented. He wasn’t even entirely sure if he was being heard. “You see it as your responsibility. But it’s best you stay behind.”. - Excerpt from Interlude 21.x
↑Four copies of the Custodian appeared before us as we made our way into the fourth floor. Each moved slightly out of sync with the others as they moved their heads. It was only when the third and fourth moved that I realized just how they were moving their heads – raising their chins to look up.
“I know, my dear,” Satyr said. “How close?”
They didn’t respond. Instead, they disappeared. First one pair, then the remaining pair.
“Second floor basement,” Satyr said. “Scion is taking his time making his way down.” - Excerpt from Venom 29.6
↑I spread my bugs out through the area. Felt the Custodian flowing through the air, a little faster than before.
She flew towards me, and I flinched, taking a step back.
She repeated the process, looping back, then charging me.
This time, when I took a step back, it was on purpose. She’d done it a second time because she wanted me to take a second step. And a third, a fourth…
“Go,” I said. “This way. Move.”
We ran. I focused on my swarm, spreading the bugs out as much as I could behind us and in front of us.
Different cells sat at the end of the hallway. Bigger cells, arranged so that they faced the opposite direction, with paths leading in, then to the right, then back into the room.
Two-nine-three. An empty, unlabeled cell. Two-six-five. Two more empty, unlabeled cells.
Bastard shook his head again, opened his mouth in an almost yawning, lazy bite. I could sense the Custodian there, brushing by the side of his face.
I moved the swarm to block the other inmate’s view of us.
“Head-” I started, but Rachel was already making her way inside one of the empty cells. She’d put the pieces together. “…right.” - Excerpt from Venom 29.4
↑“That was the basic idea. But I’ll need to do something else,” I said. I turned off the effect around it, watched as it dissolved into smoke. “Custodian.”
I felt out with my bugs. She reached directly into the swarm, letting me feel the slow movement of her hand.
“Generally speaking, you think you could handle most of the ones out there?”
She slowly floated through my swarm. The movement of her head… was she shaking it? - Excerpt from Venom 29.5
↑Custodian basically is like the guy Number Man fought in his interlude. She's a reality-breaking Case 53. Rather than get brainwashed/contained, she took on a role within Cauldron. She occupies all space within an area, but her strength is diffuse. - Wildbow on Reddit
I’d sensed it at the meeting the Doctor had arranged. The spirit, the ghost. So subtle it was almost impossible to notice. The currents of the air, the faintest of traces in dust that marked where she’d traveled… all things I’d mentally dismissed. Air tended to move. Only the fact that this was a closed space, without any kind of air conditioning or temperature difference made the movements in the air curious.
Paying attention, I could see that there was a pattern, a consistent repetition in air currents so feeble they might not have moved a feather.
The lights flickered back on, went out, and then settled in a compromise, the dull translucent pane of the ceiling lit up with a patchwork of maybe two thirds dark to one third light.
“I don’t think it’s a who,” Imp said. “Try ‘what are you talking to?'”
“Shh,” I bid them to be quiet.
I could sense more movements in the air, close… no. That was a result of Lung’s fire heating the air.
Further down the hall. If I use enough bugs, try to get a sense of dimensions…
A head, part of a torso. I could feel the contours of narrow shoulders, the waist. Female.
She disappeared, or she became less coherent, the movements in the air continuing, but ceasing to suggest a general human shape. Another appeared behind us, roughly as far away. No arms, no legs. Just a broken figure.
“I’m not getting anything usable,” she said. “Video cameras suck like that.”
“Right,” I said. Louder, I called out, “We’re here to help the Doctor! You’ve got two other groups in here, one that’s definitely hostile, angry and destructive, and another I think is worth being suspicious of.”
A movement, a reaction to that last sentence.
I explained, “Maybe they seem friendly, but they’ve got a bad history of backstabbing, making subtle plays for power. I think the Doctor would back me up on this. If she’s cooperating with them at all, she’s doing it with knowledge they’ll capitalize on any weakness she shows… and she’s never been weaker than she is right now.”
The figure turned around, briefly fading out of existence.
She reappeared in a way that made me wonder just how long she’d been there, a foot away from me.
“We’re not your enemies,” I said, holding my ground. “I want to stop Scion, and the best, easiest way to do that is to get things back into working order here.”
For an instant, she was in four places at once. Then she settled on three.
It struck me that I’d never fared particularly well against stranger-class powers.
“If it helps,” I said, “I’m pissed. The Doctor called you the Custodian, which probably means you’re the one taking care of this place. If you’re not completely emotionless, it hurts, that they’re tearing it apart. If you care about the doctor, I’m betting you’re worried. Maybe you feel like I do. You want to retaliate, but something is getting in your way-”