When I first ran Obsidian, I was mostly testing the mechanics. When the Apophis folks gave me a copy of their urban life supplement, In the Zone, I got interested in playing again and focusing more on the setting. I wound up running a free-form Obsidian one-shot, which turned out very well. Here are the details.
My main concern about Obsidian is that the background and setting are so dense that it's hard for a player to come up with a sympathetic character. There's a lot you have to know in order to envision a character that fits the setting, and the sheer volume of information can overwhelm one's creativity. So I decided to play a trick on my players.
I wrote up a player introduction (see below) for a free-form cyberpunk session, but I didn't tell the players that we were actually playing Obsidian. Key to the setting were terrorist groups, with which the player-characters could be associated. Since the cyberpunk world was similar to our own and sketchy on detail, the players found it easy to invent engaging characters with curious details.
Once the players had defined their characters roughly, I told them that actually we were going to play in the Obsidian setting. I worked with each player to reinterpret the character into the Obsidian setting. Connections to terrorist groups became connections to kults.
All character development was done secretly so that we could make the most out of secret associations to various kults.
Learning and using a new set of mechanics usually isn't worthwhile for a one-shot, so we free-formed it. Characters didn't really have stats. Instead, all contests (or dice checks) were made on 1d20, and a player would add +5 if the character had some advantage in the contest, or +10 if they had a big advantage. This system allowed me the joy of uttering such GM lines as, "Everybody make a 'notice that someone's about to toss a grenade in the room' check."
I would have resorted to some sort of hit point or wound system if there'd been a need for it, but all the characters either avoided damage entirely or died, so there was no need.
The basic idea was to let the players mess around in the milieu, then lure them to a nightclub that was secretly run by the kult of the machine, with a techno hellzone hidden on the premises. The whole club would seal itself off, the kultists would attack, circuit zombies would prowl (thanks to inspiration from All Flesh Must Be Eaten), and the climax would be a face-off in the techno hellzone. High body counts are fine for a one-shot, and dead characters can always "come back" as circuit zombies.
As it turned out, the prudent characters were more interested in escaping with their skins than fighting the kultists and zombies. I could have had their exit blocked, with a character realizing that the only way to escape would be to find the techno hellzone and defeat it, but escaping was climax enough.
The last scene of the evening was the characters climbing a ladder in a large ventilation shaft, with countless circuit zombies climbing up behind them. Everyone diced for how fast they were going, but the kicker is that you can't go faster than the character above you. The last character in line is doubly screwed. They're the first ones that the zombies are going to reach, and they can go no faster than the worst-rolling character in the party. As it turned out, the second character in line rolled a 1 for ladder-climbing speed. When the character behind her tried to climb over her, she rolled another 1, and both characters ended up falling to their doom. The rest of the party did well and escaped.
A lot of the details were ad libbed. Obsidian invites bizarre ad libs the way Over the Edge does, so I was on familiar territory. Here are two of the most successful inventions.
I figure that food in the Zone is all artificial, so its shape, color, and texture are arbitrary. People in the Zone are so divorced from nature that they don't even try to make their food look like natural food. So some NPCs in a bar were eating little blue squirming "noodles," sort of like slugs. The noodles had artificial nerve tissue that made them wriggle when touched, so that they effectively tried to escape as you ate them.
The nightclub where the action took place has a screen for every surface: walls, tabletops, chairs. So the central computer could put up 3D images anywhere and everywhere. While the PCs were hanging out, the walls showed the interior of some massive factory where a firefight was raging.
Most characters had secrets, usually involving connections to one kult or another. That's part of the setting's charm, especially for a one-shot. Partway through the evening, I suggested that we could drop the secrecy and let player knowledge diverge pretty far from PC knowledge. One player wanted to go that route, but the others wanted to keep things under wraps. If I were to do it again, I'd have said that it was up to the players to decide whether to conduct their secret actions in the open and reveal their secret thoughts. It would have been fine for some of the PCs to be "outed" and others not.
The session was extremely successful, with colorful characters, memorable scenes, and a satisfying climax. The Obsidian setting offers a lot of material that players and GMs can riff off of.
This is the intro I emailed to the players.
Here are three of the characters that my players came up with.
Dr. Moira Jones
> A name, maybe a nick-name, or your real name that none of your friends know.
> A job, a career (probably not a family).
> A hidden weapon
> A way to have some chance of surviving having a hand grenade rolled under your chair.
> A secret link to a terrorist cell (but probably not actual membership).
Moira became a kultist of the internal, aligned with the House of Sand.
Rainer became a kultist of the chemical.
A job, a career (probably not a family).
A bad thing that's happened to you recently
A criminal record
A way to have some chance of surviving having a hand grenade rolled under your chair.
A fun place to go on a Friday night; the other characters might or might not know it, too.
Here are the notes I wrote up for the adventure. It's not much, but each line was just a reminder of ideas that I had worked out in my head. My notes after the fact are in brackets.