(Missing the vestige on the pic)
The prisoners are The Vestige, The Nerevarine, The champion of Kvatch/Cyrodiil, The Dovahkiin.
So what are the prisoners?
The prisoners are a constant on the dream of the Godhead they are concept, The Prisoners are free from the chains of causality and determinism that bind the Dream of the Godhead, and have true free will to be as they are, walk any path they choose and do as they will, their freedom is so great that they are/have more freedom than the Gods themselves.
They are of any race, any gender, and can do anything, and it will be all simultaneously and equally true regardless of contradictions, as the Prisoner is an entity that exists outside all Possible future branching paths and exist as a tear/wound in reality and time.
this can be seen on ESO:
- AIOS: "Beginning entity analysis. Entity exists outside known possipoints. Transitioning to general reception array.
- Hello."
- The Prophet: "It's good to see you again. I do see you, in my own way. You are a wound in time, a tear in reality that shouldn't exist and cannot long endure."
So the prisoners will have every item they can use, every spell they can use, and will be able to act with maximum efficiency and use the best spells, shouts, techniques and attacks for the situation at hand simultaneously.
this can also be seen on C0DA:
"PIC 1: Through the breach, the gigantic form of Akulakhan looks down at all of us, unreadable hope in its eyes. Its third eye is open, with the barely discernible head of the Nerevarine serving as its pilot, the gender and race either indistinct or, if you prefer to render it this way: simply just "quantum-vibrating" too fast to tell."
- Landfall: Day One
on here u can see that they dont really have a gender or race for they are all of them
and to showcase their freedom:
"“All of this exists because it must exist. I stand here, in this place, in this moment, not because I wish to, but because I have to. A result of action and consequence.
(...)The Prisoner must apprehend two critical insights. First, they must face the reality of their imprisonment. They must see the determinative walls - the chains of causality that bind them to their course.(...)The Prisoner must see the door to their cell. They must gaze through the bars and perceive that which exists beyond causality. Beyond time. Only then can they escape.”
- Sotha Sil
The idea of this can be best describe as Tod said it:
"Go Where You want to! Be who you want to be"
- Todd Howard
And where this can be better seen is on the "new" game The Elder Scrolls Online:
- Sotha Sil: The Prisoner wields great power, making reality of metaphor. We will need you before the end.
- Vestige: Why do you keep calling me the Prisoner?
- Sotha Sil: A fool's hope, perhaps. I should explain. Look around you. All of this exists because it must exist. I stand here, in this place, in this moment, not because I wish to, but because I have to. A result of action and consequence.
- Vestige: So wouldn't that make you the prisoner?
- Sotha Sil: Clever... but incorrect. The Prisoner must apprehend two critical insights. First, they must face the reality of their imprisonment. They must see the determinative walls - the chains of causality that bind them to their course.
- Vestige: You haven't done that?
- Sotha Sil: I have. But I fall short of the second insight.
- The Prisoner must see the door to their cell. They must gaze through the bars and perceive that which exists beyond causality. Beyond time. Only then can they escape.
- Vestige: You don't see the door?
- Sotha Sil: I see only unsteady walls.
- If the people of Tamriel must exist inside this cell. I will make sure that the walls are stable, the gaps are sealed, and all who remain stay safe within it.
- Vestige: I have no other questions.
- Sotha Sil: I've met few heroes like you. Very few. I take this matter of the Triad upon myself, but in truth, you may be the one that saves us. The Prisoner who frees the world. We shall see.
- and this is not new either as it has been a thing since TES III:
- “On a certain day to uncertain parents
- Incarnate moon and star reborn.
- Neither blight nor age can harm him.
- The Curse-of-Flesh before him flies.
- In caverns dark Azura's eye sees
- And makes to shine the Moon and Star.
- A stranger's voice unites the Houses.
- Three Halls call him Hortator.
- A stranger's hand unites the Velothi.
- Four Tribes call him Nerevarine.”
- - The Seven Visions
- and another one:
- “When earth is sundered, and skies choked black,
- And sleepers serve the seven curses,
- To the hearth there comes a stranger,
- Journeyed far 'neath Moon and Star.
- Though stark-born to sire uncertain,
- His aspect marks his certain fate.
- Wicked stalk him, righteous curse him.
- Prophets speak, but all deny.
- Many trials make manifest
- The stranger's fate, the curse's bane.
- Many touchstones try the stranger.
- Many fall, but one remains.”
- - The Stranger
- And of course this would not be TES if vivec is not involved:
- “The ruling king is to stand against me and then before me. He is to learn from my punishment. I will mark him to know. He is to come as male or female. I am the form he must acquire.
- Because a ruling king that sees in another his equivalent rules nothing.”
- - The 36 Lessons of Vivec, Sermon Thirteen
- “You have discovered the thirty-seventh Sermon of Vivec, which is a bending of the light, long past the chronicles of the Hortator who wore inconstant faces and ruled however they would, until apocalypse.”
- - The 36 Lessons of Vivec, Sermon Thirty Seven
- Now that all has been said to put it simply: The prisoners are of all genders and races and exist unbound by causality and fate, they have true freedom, every action possible they have will be taken at once no matter the contradiction of it.
- now some will ask "if he is defeated on one possibility would he lose?" the answer is, not really.
- you see when the prisoners appear to save the Mundus they don't really have to do it, they are not bound to that fate/destiny/prophesy, however the actions that lead to their victory overwrite any other case on which they chose to leave and hide or lost, basically reality, fate, destiny etc. follow where the prisoner wins and discards those where they lose, in other words the only true way to defeat the prisoners is when they have absolutely no chance (0%) opportunity of winning, They are Unbound by the chains of cause and effect that rule over the dream of the Godhead.