I've been workshopping ideas for a Fate RP for a while now. It would be an AU within Fuyuki during the beginning of the fifth Holy Grail War. All of the noble mage families would still exist, but most canon characters related to Fate/Stay Night wouldn't exist/were killed off earlier in the timeline. For one reason or another, the players would be working together as hired mercenaries, loyalists or whatever else they want their origin to be, under an organization or mage family enlisted in the fifth Grail War.
This will very much not be a PVP RP where everyone gets a servant and you all try to kill each other. Rather, you're a more traditional party working together to take out the other factions. Each faction, including your own, will have a Servant tied to them, of which I will control. It'll be less about playing as Servants and more about the magecraft of the Fate universe, as it applies to combat for players. You could choose to have your Servant accompany you on missions to raid another faction's HQ and attract the attention of other factions and their Servants in the process, or be more subtle without your Servant but at the risk of being worse off if you get caught, and so on. You could also not be a particularly talented magus at all and be participating for a reason unrelated to claiming pride for your own family. It's up to you.
I would be acting as a DM of sorts, guiding NPCs and enemies. The possibility of character death or permanent damage is there, as a fair warning, considering the nature of how brutal combat can get in this setting.
After everyone has made their characters, I will randomly pick one among the party and PM them. That person will be a traitor, working for another faction. For one reason or another, they are so skilled at passing background checks and knowing the right people that they have infiltrated your faction flawlessly. Nobody knows IC that there's even a traitor at all, at least in the beginning. That person will get 1 "hidden action" of sorts per week IC that can be done in secret to sabotage the faction they're pretending to work for. These actions can be minor or major, although direct assassination attempts on fellow players would go from being private to public affairs between the traitor and target and are less likely to succeed assuming it happens at the faction HQ. Actions that would be obvious or easily discovered will also go public rather than stay as a private action. More details will be discussed with the traitor in private after they're chosen.
That's about the gist of what I'm thinking. I'm looking for 5 dedicated players for this. Any interest?