If you do end up playing a GMPC. Here is some tips based on my own experiences:

• NEVER play a Face (social character). Talking to yourself while the other PCs sit back and watch is pretty lame. and unfun for everyone
• Stick to characters that have simple shticks. All your players are already spending a couple of minutes each round sifting through their character sheets to find out what they can and want to do. When it gets back to you, you should already know what you can and should do. making simple, and straight-forward characters only makes your job easier and does not bog down the game.
• When possible, play a support character. Your entire job is to make the other PCs look awesome. What makes for a better GMPC than that?
• Give them excuses to not big participants in scenes. Maybe they are socially awkward, a mute, or only speak up when they have something important to say. The point is you are going to be so busy playing NPCs than you don't need to worry about what your own GMPC thinks and how he reacts.
• Make sure you are clear on what your GMPC knows and how he thinks. Never stop considering this when they offer advice or make decisions. You don't want your players to think that because that character is being played by someone who has intimate knowledge of the story, that they are going to make the decisions based on that meta-knowledge. Big-Dumb-Brutes are good for this. They just want to smash. So any decision that leads to combat is what they will make or side with.

On 4/28/2018 at 6:04 AM, kaosoe said:

The point is you are going to be so busy playing NPCs than you don't need to worry about what your own GMPC thinks and how he reacts.

One option is to consider how that scene/encounter will go down or how that time will be spent ahead of time, roll out any rolls that you think might be appropreate and otherwise build that reaction into the game. Keep it in the background for sure, and separate player knowledge (or GM knowledge in this case) from character knowledge when working out that scene. You have tons of prep time, no reason you have to think like a player on the fly too.

I try to avoid using GMPC's but in this particular campaign, it kind of became unavoidable.

A couple of things that I'm doing that seem to work:

1) That GMPC is the poor soul who gets to stay with the ship, when the party is in an unsavory port.

2) The GMPC is doing things that the PC's aren't skilled at (Piloting the ship & fixing things). Since this crew doesn't do a whole lot in space, that works nicely.

3) If the PC's can do something then the GMPC doesn't, or assists.

4) The GMPC asks the PC's for directions or their opinion. In other words, the GMPC is subordinate to the PC's.

Things that aren't going so well.

1) The blasted GMPC keeps getting kidnapped and needs to be rescued all the time. I'll have to stop that (starting NEXT mission).

On 4/14/2018 at 3:57 PM, kaosoe said:

I used to do this a lot when I first started GMing. It wasn't as bad as others are making it out to be. However, after a point, the other PCs were asking my character what they were thinking or what they feel the group should do next. Whether the players realized it or not, they were depending on me and my behind-the-scenes knowledge to advance the story. So once I came to that realization, I stopped running GMPCs.

I had this exact same problem. I was the GM 80% of the time with occassional relief from two of the players. It made sense to have the character I played when they ran around and it added a little extra muscle to the party. In fact, when I wasn't running these characters the other players often went and got them. I was, if I don't say so myself, very good about it. My character role-played / interacted with the other PCs and helped out, but did not take the lead or make much in the way suggestions (except when I was just a player when this character oddly became the defacto and implicit leader). But, the players kept asking my character for plot advice, so I adamantly stopped running them. With my current group there is a frequently appearing NPC that feels a bit like a GMPC, but I really don't want him to be that.