What I had in mind soo far (And I'll try to explain it very simply).
It may not be very fitting with what you are trying to go on but, like I told you, it's a "basis" we could use I guess (It's also a rather W.I.P work obviously. Much may change):


It's a story that involves both Leo\Klaire... More specifically a story that starts with them being "sheltered" in a position in which Dead figured they would have been safe from whatever devastated the world... Possibly one of his\her hideouts.
(It's likely that the U.S atleast was mostly if not entirely wiped out).

I took the inspiration from a game franchise that I highly dislike, ironically enough... I'll let you guess which.
Eitherway this is something that may end up becoming connected to the previous Story arc of N.M.D.
This also would imply that not an immense amount of time passed...
Maybe just enough for them reaching something like the age of 20 or a little more.
They both survived due to "The Tome" taking care of them (A character that... Even if I shouldn't spoil... Would be revealed of being one of it's "first" "original owners"... A.k.a "D'Sparil". One of the serpent brothers from the franchise of "Hexen\Heretic". I dunno why I suddenly decided to use more of that lore in particular. I just figured that it would have been cool especially if I tried to give it my own spin. I told ya I wanted to flesh out that character moar anyways ).

After soo long spent isolated however, The Tome would begin to show signs of extreme fatigue and exhaustion... Due to it requiring innocent souls to feed upon to continue it's survival... And it's given goal by it's "Master"... Which is the protection of his\her Children... The last order it ever received before loosing all contacts with him\her.

So the two set out to explore the vast and desolated lands in order to save the only thing that could keep them alive... And keep them "connected" to their now "defunct" family.

K and L end up separating in bad terms... Which will lead Klaire to group up survivors and slowly build up an hyper-technological city... Which she will command and administrate... Heavily "inspired" by her origins she will build it with surviving Dallz and even create new ones... Plus even recovering and reviving Silence from her "stasis" (Which served to save her A.I from soo many years of inactivity and lack of maintenance). This will lead to Silence becoming some kind of "vice-president\counselor" or something of the sort for Klaire (This also implies a society that may end up being based off the "perv" aspects of the Dallz and such. Even all of the "normal" citizens would be affected by this in the end).

Leo, on the other hand, will set out to become one of the most brutal and cruel leaders of the bandits and punks who live in the region and soon enough, the entire country.
He will frequently try to assault Klaire's city to conquer it and in an attempt to kill his sister... Altho her city defenses would end up being too good and thus the two would often meet in a situation of complete "stall" in their "war" for domination and survival.

The tome will also remain will Klaire.. protected by her, since Leo had gone soo mad that his quest also involves taking hold of it's powers for the worse of purposes.

By this point in the story D'Sparil would be able to summon back into the plane of existence (and come into contact) with people like Ann and the others...
Only problem is that no matter the attempts the only one who couldn't be raised from the dead again nor contacted would be Him\Her...

Sadly those wouldn't be the only problems... As some kind of cybernetic "infestation" slowly takes over several "sectors" of the city, forcing the survivors to camp at the "president house" and figure out a plan before another apocalypse happens... The afflicted sectors and people who become "infected" turn into disturbing and horrible monstrosities set to kill anyone who is still alive and breathing (For unknown reasons).
At the same time a rather similar "virus" has been plaguing the bandit camps that Leo is leader of... Forcing the bandits and himself to try and find refuge in the city that he so hopelessly tried to devastate and conquer...

At first noone would want that bunch around... For obvious reasons... But he seems to have an idea as to what is going on...
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That's pretty much all that I can write for now (I need to take a break A.S.A.P).
I'd have more but not only I don't wish to spoil too much.

Let me know how this sounds aye?

you have got to tell me more about this tome.
Interisting that you'd want them leading socities or settlements... I might be able to work some of that into the background of the midwest where most of this takes place.

Well I haven't worked a whole lot for the Tome character yet.
I can of already picture the guy using the same voice as "Nazeem" (Or whatever his name was) from Skyrim.

There's no doubts that he won't have much at all in common with the original D'Sparil from Heretic... But that is not something I personally mind... Obviously having more freedom to make what I want isn't bad >.>

I planned of actually "properly introducing" him in the "Wild West" RP setting you wanted to start, Assuming Dead may end up as a part of it.

(This contains spoilers for the character... But again, much like what I wrote soo far, he's very W.I.P. I'll write these ideas down in a non-orderly fashion... I apologize).

From what I could tell you soo far he's meant to be sort of a reptile\scalie
(Green colored, But that could be changed even on the spot).
Comes from a fantasy-medieval-goth background... but would do his best to "fit" in whatever scenario he's thrown into.
Infact, He loved the idea of exploring, learning and appreciating new ages of existence from all sorts of races (Altho, he has still his tastes and style).

He's swore an oath of loyalty towards Dead after he was found in the depths of Hell itself.... Forced to remain blocked by extremely powerful magics created by the God's themselves (And the "Heroes" of the prophecy which slayed and defeated him and his brothers simultaneously) ... Which tough it would have been a fitting punishment for him to be forever bonded to the book he also created (Might not be accurate towards the Hexen\Heretic lore. I should do more research on the subject when possible... Not sure if I care for that at this point).
Basically Dead saved him from an eternity of humiliations and endless pain\suffering.
The two quickly formed sort of an "intimate" friendship (But it never really went -there- ...Not yet atleast... That may soon change tho <.<).

Initially all his knowledge was what he knew on his own and what the book included "by default"... But with the years spent out and connected to all sources of information (Even the internet, and cyberspace) his power has grown massively and exponentially.
He's one of the reasons as to why Dead learned Black magic and understood the key to fully and utterly "crack" magical arts into a form of "science" that could be understood and changed\manipulated in whatever way possible.

He's also learned a lot from years spent living as a servant of Dead... His\Her habits and such.
Personality wise soo far he's kind of a gentleman and "ladies-killer".
He lives in the style of a "James Bond" (Or Bond villain, depending on how you see the "half-filled glass") sort of individual.
Never hesitates to try to impress... And there are a few occasions in which he's free to act as he wishes*...

He's also sometimes victim of his own deepest and most repressed toughs...
Meaning that he can become extremely pervert, violent... Or passionate.

And sometimes, he's also kind of a dick to people.
Especially the individuals that he wishes to "test" just to prove their worth to him and to his master...
Despite maaaaaaaaaaaybe his Master already had children with said person. (Did I mention that he's kind of a pervert? Yup ).

As for his powers and abilities, he works as an "adviser" for Dead.
However it's not uncommon for him to remain silent and stay as an "observer" of any events Dead may take part into.
He won't immediately open up to whatever individual D. may end up working with (But there are exceptions to that rule of his).
Aside that, He's also capable of spawning things into existence (Going as far as creating life up to a certain point and with some limitations) and perform powerful incantations\enchantments (Plus creating time and dimensional warps).

There may be cases, however (You never know in life), in which he may "separate" from Dead to do things on his own* (This implies that he could even go on "missions" for Dead and himself on his own accord when allowed. And he could also kill with physical means when necessary).

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That's all I can think for now ^^

Also I figured that both the siblings would be inclined for leadership and the will to obtain power... Sort of a "family thing" carried over from Dead

a bit of both depending on regions.
Now that I think on it some areas controlled by certain companies or pre-war factions were built like 1950's suburbs to be "perfect" I'm thinking areas of the midwest, on the other hand other parts of the country such as texas, are so devistated it's mad max out there.
The East Coast is sort of urban-survival ish and split between citystates that have formed a sort of confedration.
New England is the most region, and sort of acts as a "civilized land" where I can do cyberpunk stuff.