Each of the 'single-session' modules have been taking three since the Artificier joined up. But now, he is gone. Having behaved like an absolute child during our most recent session, our host (who also plays the party Bard) asked him to leave. I don't like this situation one bit. The Artificier was a rules sponge. He'd shown the most promise of any player I've ever run a campaign for in terms of learning how to play the game. He was making his first steps on the road to becoming a top-quality Dungeon Master too but he brought his exile upon himself.
The Artificer was almost ready to begin building golems, he was already prepared to build a homunculus. He had begun jealously gathering gold and loot, he'd already managed to bogart the entire 150gp advance payment to find the kidnapped sister of a worried gold elf and had about as much money as the rest of the party combined. An opportunity came for more cash to line the party's pockets but his behaviour was grating on the other members and they decided to withold his share of 200 coins until he started being a team player. The dungeon was clear, only one locked door remained and the Artificier had the key to it. As he was also the party lock-opener they needed him to open the door.
In exchange for the key he wanted all 200 gold from the last lot of treasure. If they refused him then he would throw the key down a nearby chasm and escape the dungeon with all of the horses and all of the loot. Paladin was not there so Artificier was playing his character. The rest of the party said that Artificier's plan was evil and Paladin would try to stop him, Artificier disagreed, claiming that it was not certain that the prisoners were behind the door. This was when I stepped in, saying that the prisoners must be behind the door as it was the only place left in the dungeon short of an underground river that they hadn't fully explored and that if he carried out his plan, it would indeed be an evil act and thus disallowed. The party made Intimidate checks to get Artificier to hand over the key and succeeded, however Artificier still planned on looting and leaving with all the horses. I asked Artificier to stop as the rest of the party were becoming very tense and after he once again refused, Bard told him to leave.
I don't think the group will allow Artificier back and I'm not going to be able to replace him until September when Druid's original player is supposed to return.