Even among her fellow Fallen she is described as "off", despite her obvious intelligence.
She is, by all accounts, a true believer in the ideology of the Fallen, and willing to kill members who disappointed her and their families.
She has a extremely regressive view of gender roles, while at the same time an surprisingly progressive stance. Anyone can occupy any position within the family they want as long as they are dedicated to the "cause" and have powers. Everyone else is disposable.
Mama is an emaciated women, heightened by her thin face and long hair that bleaching has rendered frayed and silver. This gives her the presence of an older woman, despite the fact that she is in her thirties, and makes her look fragile enough she could break. However, to people that were affected by her power she felt 'heavy'. She generally wore white, as did every other close family member of hers.
Mama's power grants her the ability to induce hallucinations in anyone who percieves her, with the degree of control depending on how clearly she was percieved. The nature of the hallucinations depends on the senses through which she was perceived. If they register her presence with any part of their Sensorium, including any granted by parahuman abilities, that sense is then affected. Most often, this involves auditory and visual hallucinations, though it is crucial to note that physical contact with her can result in her inflicting excuciating pain at will on her victims . Mama herself can also sense through the infected senses, including anything provided by a power.
Since sight is the most common method of perceiving her, hallucinations can often manifest as if they have a Dybbuk of her imprinted on them. This dybbuk can interact with the imprinted person through the infected senses. Anytime a subject mentions Mama in any way, writing her name, talking about her, even thinking about her, a phantom image of her appears in their field of view and takes in the surroundings. It is unknown what her ceiling is for how many subjects she can affect, how the distance over which the connection is sustained, or how much information she can process. Regardless it is enough for her to create an ad-hoc communication network between those she has affected, and carry on whole conversations without needing to speak.
Her power acts as a harsh anti-Thinker ability that allows her to keep her kin covered from snooping eyes. Those with any power assisted perception of her feel for the effect.
She is likely a Noctis cape, based on a preponderance of evidence.
It is known that she can rescind her connection for a time, it is unknown what criteria are needed to reestablish it. Much like 'disconnecting' causes people to hear the sound of wings when they think of her; the effect might also tuned to cause powerful and disabling hallucinations. People who are only fleetingly register her in some way are still affected if only nominally, this can still be enough to blind deafen and distract people.
She was abandoned by her family because of her teen pregnancy. Her kid was an exceptionally early trigger, manifesting powers before he started walking. She was somehow found and saved by Cauldron, which offered her a deal. She was lucky enough to gain power that allowed her not uphold her side of the deal, unless she wanted to.
Joined the Fallen and presumably founded the Mathers family. Had several children from multiple different fathers, such as Valefor and the one who called himself Lionheart. She also traded children to other branches in order to get firepower back.
Under Teachers grasp, her health improved, and she actually started to look her age.
Teacher used Madam Mathers ability to entrap a large crowd of people in Earth Cheit, including local leaders. She was given free reign over them. She used her abilities to shape their beliefs in the ways of the Fallen.
↑William, Scapegoat, was catching up, drawing nearer to the Thomais Fallen. Elijah, Valefor, walked arm in arm with his mother, Madam Mathers, who wore an ethereal white gown with a shawl around her shoulders. Her health was better since coming here, since she’d been… helped, with firm boundaries. She looked closer to her actual mid-thirties than the weary young crone she’d been before. - Excerpt from Interlude 13.x
↑ 2.02.1The idea of losing my mind like that terrified me, to the point I felt like my gut and my brain were bound in knots. I tried to focus that terror into a cold, rational look at what I needed to do. Mama Mathers was the biggest danger. Valefor was the second. They were Masters and Strangers, the PRT classification for those who controlled others or minions, and the classification for those who infiltrated or deceived. Mama Mathers and Valefor were squarely in the overlap between the two. - Excerpt from Shadow 5.12
↑ 6.06.1“Rain,” she said. “Look at me [...] I will have you killed if you do not,” she said.
He’d only seen her leg and foot, and she’d jumped into his head, tactile, audible, present, impossible to ignore. [...] “Why would you leave, when we haven’t talked?” she asked. “You’ve been standing there, talking to yourself.”
“Sorry, mama,” he said.
He knew how she worked, but he couldn’t ignore the apparition in situations like this, because ignoring her and having her turn out to be real was the sort of thing that got him killed.
“Everything I said to you before now, it came from within you. I saw and heard much of it,” she said.
↑Her fingers traced his shoulder-length hair. “I told you to grow your hair long, back then.”
“Yes, mama,” he said.
“Do you remember why? Any boy of mine that does anything to catch my eye, good or bad, I have them do it. [...] The girls know it, but the boys sometimes need to learn it. I’m content to let either be my soldiers, but that requires zeal. Not everyone has it. Not everyone cleaves to their role and position. Everyone has responsibilities, and it takes a soldier to obey.”
Rain nodded again.
Her voice took on a different tone. No less ethereal, but haunting-ethereal, now. “The hair is to remind you that if you won’t be a soldier for the families, we’ll have you be a slut. We’ll get children out of you. If you fail at that, if they’re sickly or disobedient, we’ll geld you like we would any of the farm animals.” - Excerpt from Interlude 4c II
↑Rain averted his eyes, but he could see the white drape of the nightgown, the feet on the floor. She was sitting so the post and the sheer drape kept him from seeing a lot of her.
But he saw some. Her presence jumped into his head. He looked away, but it didn’t help.
Mama Mathers. Taller than him, gaunt, wispy of hair. She wasn’t old, but she had the presence of an old woman, thin enough that it seemed like she would break or crumple into a heap if struck. She stood right next to him, leaning over him. She touched his face, and he flinched. [...] He’d only seen her leg and foot, and she’d jumped into his head, tactile, audible, present, impossible to ignore.
Now, seeing her in full, it was more pronounced, heavier, insofar as the frail woman could be ‘heavy’. Her hair was long, bleached silver, and frayed. Her face was thin enough that it appeared older. - Excerpt from Interlude 4c II
↑ 11.011.1Byron spoke up, “Can you take a message back to her?”
“I don’t know,” the biker woman said, sullen. “I don’t-”
“What?” Byron asked.
“She says no, no messages. Other stuff. She-”
Her eyes went wide. She looked around, her eyes not focused on anything in particular.
The woman’s voice carried forward, but it was an inarticulate sound, one that became higher, then a warbling shriek, followed by a gasp for air with a sound of its own.
She dropped to the ground, fingers clawing in dirt, twisting like she was trying to get away from everything at once. The noises she made were horrible, and I’d heard some awful noises in my life. - Excerpt from Shadow 5.8
↑ 13.013.1If you see her, she can visually appear before you. The more you look at her, the easier it is for her to appear.
If you hear her, she can speak to you. The more you hear her, the easier it is to appear.
If you touch her, she can give you the sensation of touch. The more you touch her, the easier it is to appear.
When she appears, she seems to be able to sense things around her image. Sometimes it's not her, but other things, like a sound of beating wings, spiders, or blood.
At the most basic, she appears if you refer to her by name, in word or writing. As you get more exposure to her, it happens if you think about her, if you refer to her in abstract, or if you even think about her in general, like not wanting to think about her.
If you use a thinker power? Effect is stronger, and affect things other than sight/hearing/touch. - Wildbow on Reddit
↑ 16.016.1The Fallen are slippery, and the reason they haven't been wiped off the map is that they utilize a cell structure and have some cover from parahuman abilities. Valefor's mom in particular. A thinker doesn't want to go scanning tracts of rural/unpopulated area for missing kids if it means a chance of seeing her looking back at them. Because if they do, then they'll likely end up in a brief coma followed by a year and a half of something like being convinced the walls are bleeding spiders. She has kids with buds from the same shard and farms them out to other branches of the family in exchange for some muscle (Eligos being some of that). Not that same degree of punishment or screening, but stuff in that general vein. - Wildbow on Reddit
↑The woman’s hand, spectral as it was, felt real as it touched Rain’s hair. He flinched, but she persisted. He remained where he was, head turned away, neck stiff.
“This was good,” Mama Mathers said. “I’ll reward you.”
He didn’t move a muscle.
“Enjoy your evening, my soldier. Tomorrow, we show them we’re not to be trifled with.”
Rain turned his head, to look for clarification, but she was gone. There was a distant sound, like a flock of birds taking off.
He’d slept on the train, but this whole scene was so surreal. She’d-
He stopped, bracing himself for her appearance. For the physical contact.
She hadn’t appeared. The sound remained. A thunderous flapping, far away.
Mama Mathers, he thought.
There was only the sound.
She’d freed him? For only tonight? [...] Mama Mather’s disconnected presence was like bird’s wings against the exterior of the house, rustling. - Excerpt from Interlude 5d II
↑I changed course, flying back to where I’d been. I continued down the street. I was putting the bulk of the lopsided engagement behind me, passing by Rain, by two twenty-ish capes with steel-gray hair, and that meant I could fly faster. I kept my eyes on the people and goings-on behind me.
I found what I was hoping for. The screaming, just briefly, changed. The aura extended through the hostages to Mama Mathers, and she affected the hostages in turn. I had a sense of my range, and through that, I had a good sense of her location. - Excerpt from Shadow 5.12
↑“What about the ones who are hooked into bigger groups?” I asked.
“That gets more complicated, and it’s less about the places to watch and more about the names to keep an ear out for,” my dad said. “Marquis, Goddess, Lord of Loss, Mama Mathers, the Crowley brothers, Deader and Goner, Barrow.”
I knew the names and I knew where they were situated. No big surprises there. I nodded to myself. Marquis. So casually mentioned. - Excerpt from Glare 3.5
↑“It’s been years,” she said. “You only think about me a few times a day. I thought it was time we were reacquainted. You have your mission.”
“I’ll kill my cluster.”
“And be a loyal soldier. Think of me,” she said. “If you don’t, you know what will happen.”
“Yes mama,” he said.
“Allie. Your aunt and uncle. Erin, her family. And you won’t see me. You’ll see other things.” - Excerpt from Interlude 4c II
↑Time is of the essence. In a day, things might be too far gone. Your Mama Mathers, Rain, is gone. They’ll find out soon. - Excerpt from Gleaming 9.2
↑The Overseer watched as Madam Mathers had her moment at the front of the dais. Center of the stage, just behind a short, balcony-like fence, stairs covered in red velvet stretching down to the city street on either side of the dais. She watched as nearly every eye present looked at the woman.
With that, with one fell stroke, Teacher assumed the ability to cripple the capitol of Earth Cheit. - Excerpt from Black 13.x
↑The Wardens are considering discontinuing the sedation of the real Christine Mathers, but as you can imagine, that’s not an easy decision to make.” - Excerpt from Sundown 17.4
↑Not sharing Valefor's mom's power, as she's interesting enough I want to keep her in my back pocket. - Wildbow on Reddit