GM-less RPG suitable for a violent spacefaring game played over a messaging client? [closed]

Question

I've been GMing for a long time, without actually playing a game myself, so I'm rather in the mood to actually get involved in the action as a protagonist, however no-one else in my group wants to act as a GM. I've already considered the idea of a GMPC but decided it's not something I want to risk. I've been GMing Apocalypse World-derived games for a while and the idea of protecting a character who is still effectively a NPC gives me a nervous twitch.

The setting that my group (including myself) has decided they want to try is a spacefaring mercenary crew in a gritty dystopian future. For the anime buffs out there, we're looking to evoke something along the lines of Cowboy Bebop but with a focus on armed conflict rather than bounty hunting. Not really looking for large-scale battles, but for participation in smaller skirmishes or side-objectives to larger campaigns.

I believe the Warhammer 40k setting is also similar to what we're looking for. Unfortunately I'm not familiar enough with it to draw a more meaningful comparison here, just food for thought.

With that in mind, I've narrowed down what I'm looking for to the following list of requirements.

GM-Related Requirements: The system should fit at least one of these criteria.

• Does not require a GM.
• Rotates GM responsibilities between players
• Allows the GM to have a PC without causing a conflict of interest or even any perception of such from other players. I don't personally feel this is possible, but I'm open to being proved wrong.

Other Requirements: The system should also fit all of these.

• Suitable for an extended campaign with 3-5 players.
• Requires no props other than dice. The game will be played on a messaging client that has a dice roll command, but no other RPG-related features.
• Rules-Light: Mechanics should be simple and applied only when it's critical. Apocalypse World and its derivatives are along the right lines in this respect, but very much require a dedicated GM.
• Can be used to play a space-faring sci-fi setting straight out of the box. Either because it's designed for such settings or it's genre-agnostic and provides the tools to create setting-evocative mechanics.
• Is not a system which relies on an existing canon universe. Myself and at least one of the other players feel creatively restricted when playing within an established canon.

Desirable but not strictly necessary:

• Has built-in support for vehicle-to-vehicle and infantry-to-vehicle combat. Double bonus for mechs specifically. Systems which function fluidly without needing rules for this also meet this criteria.
• Evokes the desired setting by design i.e. explicit mechanics for interstellar travel and other dangerous space-faring activities.
• Supports inter-PC conflict, or at least doesn't fall apart when the characters throw anything more than harsh words at each other.
• Focuses on character's emotional development. Even in the grim darkness of space people have history and emotional baggage. Dealing with this should be part of the narrative.
• Freely available or at least low-cost. It will be difficult to get player buy-in if they have to spend more than about £5 GBP (~7 USD).

Further notes on the GM-with-a-PC criteria

I didn't actually expect many answers where systems were being offered under this premise, so I didn't really elaborate, however every answer I've received to date has cited a system where a GM is the default case.

While I'm leaving my options open on this front, this is not ideal and I'll require serious convincing that this can work without causing social drama. My group has had bad experiences in the past with other GMs favoring their railroaded narrative and GMPCs over our own actions and as a result are rather hair-trigger sensitive about such things. Answers which cite a system under this criteria should provide personal experience with playing in such a manner and how such drama was avoided.

Prep work for the GM in this case should also be minimal to none, I've got a busy life and preparing material in advance for a game I'm supposed to be playing for fun is just a no-go for me.

Answer 1

I am currently creating something that almost meets your requirements: Sacrifice

I started this as a nWOD Stargate SG1 hack a long time ago, but built and entire Universe that has nothing to do with SG1 by the end. I'll just grab your text and answer bullet by bullet:

Please forgive my typo, this got very long very quickly

GM-Related Requirements: The system should fit at least one of these criteria.

• Does not require a GM.
• Rotates GM responsibilities between players
• Allows the GM to have a PC without causing a conflict of interest or even any perception of such from other players. I don't personally feel this is possible, but I'm open to being proved wrong.

All players on are on same vessel, and face the same threats. I have run numerous NPCs on-board (although most were antagonists) and those NPCs were in just as much danger as the crew.

Other Requirements: The system should also fit all of these.

• Suitable for an extended campaign with 3-5 players.

I ran for a year with 3-28 (Twenty-eight people played on night, bad move on my part) people, with a typical turnout of 8-12. 3-5 would be plain easy.

• Requires no props other than dice. The game will be played on a messaging client that has a dice roll command, but no other RPG-related features.

We played on a real tabletop with dice-only. I'm trying to rebooting it now in Roll20, but that piece remains the same.

• Rules-Light: Mechanics should be simple and applied only when it's critical. Apocalypse World and its derivatives are along the right lines in this respect, but very much require a dedicated GM.

I hate rules and rules-lawyers, and focuses on making this a storytelling game overall. I feel the rules are pleasantly simple.

• Can be used to play a space-faring sci-fi setting straight out of the box. Either because it's designed for such settings or it's genre-agnostic and provides the tools to create setting-evocative mechanics.

Sacrifice is targeted to near-future dystopian sci-fi.

• Is not a system which relies on an existing canon universe. Myself and at least one of the other players feel creatively restricted when playing within an established canon.

I invented the Sacrifice Universe from scratch, and while it is designed with a couple over-arching ideas, you could very easily populate this game with all your own settings, characters, species, etc..

Desirable but not strictly necessary:

• Has built-in support for vehicle-to-vehicle and infantry-to-vehicle combat. Double bonus for mechs specifically. Systems which function fluidly without needing rules for this also meet this criteria.

Once I finish porting this over, the system has rules for mech, vehicle (spaceships) and fleet combat mechanics.

Aside: Funny story, so I didn't have fleet combat in the game, and was morally opposed to it. I made the mistake of saying this out loud once. A few weeks later, The Players manage to from a fleet and immediate go attack another fleet. Having 160 ships brawl with full compliments would have been over ten thousand dice if played out. I had to end the game that night, and spent the next week designing fleet combat rules based off of Exalted.

• Evokes the desired setting by design i.e. explicit mechanics for interstellar travel and other dangerous space-faring activities.

Sacrifice has those, including what terrible things happen when you FTL inside a gravity well or do not have proper coordinates.

• Supports inter-PC conflict, or at least doesn't fall apart when the characters throw anything more than harsh words at each other.

The nWOD corebook has that stuff covered, although I heartily discouraged such activities.

• Focuses on character's emotional development. Even in the grim darkness of space people have history and emotional baggage. Dealing with this should be part of the narrative.

This was true, but it was causing a lot of problems with new players, and veterans were kind of form PTSD-like symptoms over time... The way they act, both in and out of character, was extremely jaded and anxious. I almost feel I should warn you away from this.

• Freely available or at least low-cost. It will be difficult to get player buy-in if they have to spend more than about £5 GBP (~7 USD).

The nWOD corebook costs money, but only one person really needs it, since only the core rules are referenced. Most of the actual gaming happens in the Sacrifice ruleset.

Summary:

Sacrifice, once it is a lot more polished, might be the game you are looking for. Here is the invite link. We play every Saturday at 1800 PST, or Sunday 0200 Zulu time, if you wanna check it out.

tl;dr:

Try my game, I think it meets your requirements.