Poor DM. All he wants is to run a coherent storyline with a consistent cast. And yet, real life keeps getting in the way. If one player's not going to a beer convention, another player is having a baby or catching a cold or getting kidnapped by aliens. What happened to the days when everyone respected the game? Well, we're no longer teenagers, that's what. Adults have different priorities and less free time. The unfortunate result is that you just can't find six people who have the freedom to commit to every single week.
The DM books always have a few tips for what to do when a player can't make it. Things like have their character fade into the background, or have someone else run the character, or just have the character split from the party temporarily. These are all acceptable methods, but what do you do if you know from the beginning that a player is only going to be able to make every other session?
Of course, some DMs don't mind just hand waving their absence, concentrating on the story more than the actual characters present. But other DMs really want to account for every character's location at all times. If it were me, I'd want to use it. Why just apply duct tape to the problem, when the problem itself is a potential plot hook? There are several good ways to integrate sporadic absenteeism into the story. For example:
Early in the ToEE campaign, we had two players who were only planning to make alternate sessions. The DM's solution? Make a character they both like, and have them share. Unfortunately it didn't work out as well as it looked on paper (one of the players didn't like the character, and the other player never joined the campaign), but it was still a good idea. Still, let's spice it up a bit. This game takes place in a world where magic is common; why let it go to waste? And why try so hard to make a character that both players like? Here's some of my alternatives:
Peppy the Halfling Rogue and Bjertha the Dwarf Cleric are a pair of treasure hunters. One day they happened upon a witch's treasure. The witch caught them and demanded they remain as her slaves. Peppy, being a smooth talker, persuaded her into just taking one of them. But which one? Finally they decided to split the punishment, so the witch placed an unusual binding spell on them. The result is that one character is always tending to the witch's needs, while the other is out questing with the party. At certain points in time, they magically switch places. Perhaps there could even be times at which she temporarily lets them both free, for the rare occasions when both players show up. It could even be part of the campaign's story arc to free them from the witch's control.
Or how about this one? Doctor Jackel is a Human Mage who was experimenting with a new spell, when it backfired and cursed him. Now, at random times, he is transformed into the monstrous Mister Clyde, a Half-Orc Barbarian. When one player makes the game, he's the good doctor. When the other player makes the game, he's the brutish Clyde. And then there's the Ladyhawke method - Gelf is a Wizard with a hawk familiar. The hawk sometimes changes into Zia, a Beastmaster Ranger. Zia's pet wolf is really Gelf... but they're never both humanoid at the same time.
Of course, the above ideas only work if you're in a very specific situation, where you know two players are going to alternate their attendance (or you have someone always ready to sub for the one who misses a lot). If you just have one problem player, here's a few more ideas.
This is what we're doing in our current Pathfinder campaign. We have a couple of players who aren't really into gaming just yet, so we're letting them contribute as much or as little as the feel like at the time. Our party has a couple of guides, who double as MacGuffins when the plot demands it. Our situation isn't quite the same as the focus of this blog, but it's not a terrible solution for players who miss a lot. Just have the DM run the character as an NPC when the player isn't there. The downside: If it's just a torchbearer, then the player can't really build a kick-ass character. Also, you'd want a way to explain the character's personality changes... why does he join the fight some weeks, and just stand back other times? Eh, we can get a little more creative than that. How about...
Rexx is the victim of a werewolf's curse. But rather than changing with the moon, he changes randomly. He's human when the player is there. When the player is absent, the wolfman runs off into the woods (or the DM runs him as an NPC when plot-appropriate). Of course, this also gives many opportunities for side quests as the character tries to break the curse. It also adds a lot of potential conflict as the rest of the party deals with the hostile wolfman and keeps him from attacking other NPCs.
The party finds an old automaton - it could be a rock golem, or an enchanted suit of armor, or even a gnomish clockwork man. It still works, but only sporadically. Sometimes (when player isn't there) all it does is follow the party around, maybe holding a lantern. Other times, it is a mighty war machine. Maybe one member of the party takes responsibility for it, and is constantly polishing the mechanoid and tinkering with its settings.
If the oft-absent player doesn't mind playing an animal, perhaps he could actually be another player's pet or familiar. For whatever reason, this particular animal can only be summoned at random times, to coincide with the player's attendance. Fluffy is a large talking mastiff, who wanders away to hunt at random times, tracking and rejoining the party whenever Fluffy's player attends a session. Shelly is a sapient armadillo who has to spend a certain number of hours a day rolled up into a ball, carried around by another character when the player isn't there. Perhaps they work more like Drizzt's kitty, being summoned from a small statue or magic gem. Maybe they even spring from a Pokeball-like device.
After a nasty encounter with an evil Wizard, Rocky was transformed into a small stone. His friends managed to work out a counterspell, but it only works for random amounts of time. Whenever he's a stone, another party member carries him around in their pocket. Or perhaps he's trapped in the reflection of a pocket mirror, or contained in a magical amulet, or even lives in a magic lamp.
River is a convict who lives in a magical prison. She has found several ways to escape, using a magic portal which always transports her back to her party. But her captors are able to track her, and usually manage to catch up to her after a few hours. Then they teleport her back to her cell, increase her sentence, and fruitlessly hope she won't escape again.
Viva was killed by a mystical trap, but her will was too strong to be completely pulled into the other side. She now lives a part-time life, phasing in and out of existence. Sometimes she is a normal human, and just as solid and vulnerable as any other party member. Other times she is in a ghost form, invisible and intangible, and can do nothing but follow her friends around and watch.
These are just the ones I could think of off the top of my head. I'm sure there's many more ways to explain a character's absence. You might even come up with an explanation for every member of your party, just in case they miss. If you have any favorite methods of your own, please post them below!