I ran a fairly long campaign of EP. The system is clunky mechanically. The setting concepts are not well thought through, so I had to do a lot of house ruling on how nanofabs, reputation, and ego-casting worked in practice.
But it is a fun crazy setting. My Firewall campaign started with the PCs being awoken and told that they were the backups, and their former selves had gone missing. They had to retrace their own steps. Later they discovered that their former selves had all become exsurgents and needed hunting down.
Interesting. Could you summarize some of those? Again, some things like Reputation as a system just seem like a dead letter when you combine it with even just normal egocasting (can you spam-egocasts and have every fork request something before the org realizes that you've hit them with a speed-of-light-based timing attack), much less actual problems like identity theft or, uh, actual-identity-theft, where you steal someone's ego, psychosurger it, and spin up a copy and have them ask for stuff on your behalf.
In terms of the fork swarm business, I handled that by telling the PCs that if an alpha fork existed for more than a few minutes it would become an NPC under my control. It may develop its own ideas about sticking to the plan and then being deleted... Alpha forks are essentially no different from the character and they would not want to be psychosurgeried or deleted.
Yeah, the trick there is to start by psycho-surgerying yourself to remove any vestige of concern for personal continuity or identity, so that you identify as much with any instance of you that exists as the one you happen to be. If you don't start from there, then your forkswarm will break down into a struggle of each fork for resources. And the thing is, the setting has people working with their alpha-fork instances in the long term in a successful manner; one of the crime families is literally one woman who abused the forking rules (but not the implications of infomorphs).
And the thing is, the setting absolutely says that someone with the right tools can say "Fuck what you wanted to be before, you are now a drone for my all-consuming swarm will, even if that would horrify any normal person." because, you know, Exsurgent. Just as the PCs didn't get to stick with their Exsurgent selves and say "Lol, no, I ignore that brainwashing and horribly abuse my gamma psi sleights.", the GM shouldn't be able to say "Well, you crit that psychosurgery roll (due to horrible parallelized retry attempts) to make the copy of yourself act a certain way, and minds can definitely be modified to act that way, but I'm going to have that NPC ignore its brainwashing and start trying to overwrite all the other forks with random ego and preferences it made up from the aether due to remarkably selective cosmic event bit-flips when it got copied."
I also think that while this is a great solution in-play and that any players who ask too many questions should be met with "Yes, I know, we're just agreeing not to look at this closely to enable the kind of genre game we want to tell.", I really have to wonder what taking your rules would do. I mean, a naive ruling would be that egocasting kills you, because the you that gets sent in transit is an alpha fork and most egocasting is a destructive read, so your PC dies and another character completely identical to your PC wakes up and goes on an NPC-only adventure...
But of course that's silly and a degenerate example. But let's make things interesting. What if the PCs are stuck in a situation like the one in the 1E intro fiction, where they have limited broadcast time and Exsurgent closing in. What if they've got themselves from a few minutes ago backed up, and now need to slowly beam themselves out line by line, and their actual-selves need to spend all of their grit, effort, and Moxie defending the transmitter array? If they succeed, do they just die, since they have now absolutely diverged from their backups, and now people who are definitely not them will instead again wake up and again go on all-NPC adventures from that point on?
What the setting assumes, I feel, is that you have a soul, and that your soul is like the green emerald thingy from the sims; it marks you as you, it exists outside of the game layer, and it is the interface that lets you-the-player decide the actions for the character. And, crucially, that there's only one per special character, and that the emerald thingy can jump to whatever instance of you is relevant to the story happening now.
Honestly, I think that the most interesting story you could tell in Eclipse Phase would be a specifically meta story, where you explored situations like this, and had one perverse player who literally stopped playing the game by NPC-ifying his PC and then sat back, letting the GM play the former-PC and horribly ruin the GM's own encounters, and jumped back and forth between in-game and tabletop cameras, and used that tension to dig into what that green emerald perspective meant, and what support that view of the world could have even when it wasn't being deliberately attacked.
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It's a pity, I think, because the Eclipse Phase setting has a bunch of interesting ideas, and it says as part of its very tagline that your mind is software to be reprogrammed. And software that can be saved to and restored from cold backup perfectly has no inherent soul, spirit, or distinguishing nature which splits it from other running instances of it. And then the setting goes ahead and includes the one-woman crime family, and Exsurgent in the first place. And as long as Exsurgent is a setting element, then there is absolutely a justification for a Mr. Forkswarm to exist and have countless running parallel versions, rooting through transhumanity like a horrible parasitic wasp. And the further thing is as long as anyone can do horrible forkswarm tricks, and as long as Exsurgent exists, then the only sane (for a sociopathic hit-the-posthuman-floor-and-pulled-out-the-excavator value of sane) response is to rip through transhumanity yourself as fast as you can, because the moment that Exsurgent starts fighting smart and going loud, it will do so as effectively as you can.
Actually, did you do anything interesting with Exsurgent? As-given, it frankly sucks, and makes the setting worse in ways both gross and subtle, but I think there are a lot of interesting things you could do with it if you don't just make it a weapon (and say, by implication, that this is what powerful and effective NPCs in the setting use when they want to shoot something dead.)