My group and I just migrated from a DM whose very incongruent storytelling and deliberate punishment of non-hack & slay-solutions scared us off. We (mostly) kept our characters (since they are our first and much thought went into them) and decided to rotate GM-duties.
I am the first to GM, 3 sessions up to now, and I ran into many problems.
The social dynamics: we work as a team in a small theatre company. One of the players is my girlfriend. Another is a cool, funny guy. Both have very little experience, but playing with them is good fun. Along with the second session comes the third player: very experienced and all kinds of problematic.
Problems with the character:
First he builds some tripping monk, which is awfully weak compared to the other guys. He hates that character, so I help him kill him off and allow him to build a new one. (using the resurrection of their friend as a plot hook for the others).
The new character is a Ninja2 / Fighter2 / Chainmaster1. with a blooded template.(by the way, about two third of the build is the same as my girlfriends´) He assures me that the character isn't that strong. That the Ninja is only there for the skills.
Today, he went invisible, crept behind three bowmen and killed them all by Attacks of Opportunity when they fired. (without breaking invisibility, because ghost step is weirdly worded...)
The encounter was laughingly easy, because he had an ability I didn't know worked that way. I feel tricked, because he told me that the Ninja's ghost step wasn't a big deal, yet obviously planned to use it exactly as he did. How should I react.
I want to mention that I do not resent good feat combinations in any way. I just do not like the nasty surprise.
Problems with the Person
He's, theoretically, a nice guy. He knows the rules far better than me. But he is so desperately squeezing for advantages. Every enemy he strikes at is flat-footed for some reason. An enemy fumbles an attack, losing his weapon: he does not say a word. He fumbles: bloody murder on how losing weapon on fumbles favors the critters. He advises me to nerf the abilities of the other players and nags about it. He doesn't tell me how good his abilities are.
And on the social side: I played the first session without him, Girlfriend shy but active. Since: Whenever I ask her something, he gives advice. Girlfriend doesn't say anything anymore. He bogs the game down with lots of rule lawyering. He is loud.
He really challenges my motivation.
I mean, he is loud and uncaring all the time, but D&D seems to pull out his very worst.
He sure doesn't mean to be. He just does not seem to perceive when he is behaving badly.
I do not want to start an argument (he starts blocking completely) and I´d rather not have to "forget" telling him when we play. I´d really appreciate advice on how to resolve this problem.