These rules were created for handling the character Prymja's (then Daniel's) multiple personalities. I've tried to make them general enough to handle other characters as well.
Dissociative identity disorder is a pretty rare psychiatric condition where a person displays multiple identities or personalities. For a diagnosis, at least two need to control the body at different times and they can't be a side-effect of something else. There is often memory loss between different identities, but this does not have to be the case. Identities -- a.k.a. personas, alter egos, or just alters -- are typically created because the original person encountered a traumatic situation that they could not handle on their own. Instead of facing personal trauma, a new identity was created to deal with that situation and with others like it in the future. As such, each alter has a few responsibilities that it was created to handle. Though each alter may be capable of acting in other circumstances, this is by no means guaranteed. In game terms, DID is a severe derangement. For more info, take a look at Wikipedia's article on DID.
When adding an alter, remember that it has a pretty specific reason for its existence. These questions may help you make each alter a unique person.
What created it? Describe in detail the situation that created the alter. This has to be something traumatic to the core personality, otherwise it wouldn't need a new alter to handle it. Then, figure out what effect that had on the parent identity and on the fledgling alter, especially how it shaped the alter's attitudes. This is the alter's birth, so make it count!
Is the alter independent? There's a world of difference between an alter who can live on its own and an alter who only knows how to handle a single kind of situation. Decide what kind of alter you want your character to have and follow through on the ramifications. If you have a high-functioning alter from being kidnapped, maybe it does the dishes some nights.
Can it remember? Can you? Memory is all-important between alters, so work out which ones have which kinds of memory. Useful considerations include which ones share memory, which ones black out when not in charge, which ones can hide information from others, etc.
Can it Talk? Of course your new alter can talk when it's working your body, but can it communicate otherwise? Inactive alters locked away in your head may very well talk with each other. Any alters that can do this must have a complete memory, otherwise any behind the scenes discussions will devolve into a bad amnesia joke.
Each alter should have a few spheres of influence, which are situations or skills that the alter is responsible for handling.
Primary spheres are the real core of the alter. They're the strongest of its responsibilities, and may be the only spheres present for a specialist alter.
Secondary spheres are less central to the alter, but still follow the same theme as its primaries. It's a good idea to branch out a little at this level, since these spheres define the peripheral responsibilities of the alter.
Tertiary spheres are the alter's least important interests. They should still relate to its primaries, but the connection can be awfully tenuous.
Regardless of level or alter, no two spheres should overlap. If they do, refine them to highlight the differences and ensure that only one will apply at a time.
Hand-in-hand with the spheres are the alter's skill specializations. Your character sheet as written deals only with your main identity. When adding a new alter, you can reassign one or two skill specializations to reflect the alter's sense of priorities. These reassignments need to make sense and should add to the alter at the expense of the original identity. The new specialties will only come into effect when that alter is in control.
There are always going to be situations that you can't plan for, and that you don't have a sphere for. That's OK! When they happen, work with your storyteller to come up with a solution on the spot. Likewise, don't stress about adding every possible detail when creating your alters. It's fine to leave things up in the air until they happen in a session.
Now that you've established the alters for your character, you can put them to use. Any time your character is in a situation governed by an alter's sphere, that alter may try to take over. Depending on the alter, it might choose not to do so.
If an alter tries to take over, the current identity can simply cede control, or it can fight the change and resist being pushed aside. If your character tries to resist a change, the current identity makes a Self Control roll as stated below. If it fails, then the alter takes over and runs things according to its own agenda. Even if it succeeds, though, the alter can keep trying to emerge every time its spheres are immediately relevant, forcing another Self Control check. Those checks suffer the usual penalties for consecutive retries.
When an alter takes over, the alter's skill specializations replace the designated ones from the old identity. All special and normal abilities are then under the sole control of the alter, including supernatural abilities like the appearance changing of Mirrorskins.
Dice Pool: Resolve + Composure + Modifiers
Action: Instant
Roll Results:
Dramatic Failure: The current identity loses any control it had and cannot reassert itself for the duration of the scene.
Failure: The current identity is pushed aside by the alter.
Success: The current identity maintains control and resists the alter, for now.
Exceptional Success: The current identity asserts itself over the alter. That alter cannot again attempt to emerge until the current identity either gives it control voluntarily, or is pushed aside by a different alter.
| Modifier | Situation |
|---|---|
| +3 | The current situation falls within one of the active identity's primary spheres of responsibility. |
| +2 | The current situation falls within one of the active identity's secondary spheres of responsibility. |
| +1 | The current situation falls within one of the active identity's tertiary spheres of responsibility. |
| -1 | The current situation falls within one of the alter's tertiary spheres of responsibility. |
| -2 | The current situation falls within one of the alter's secondary spheres of responsibility. |
| -3 | The current situation falls within one of the alter's primary spheres of responsibility. |
As your character continues to grow, its alters grow with it. Any time you buy a skill specialization for your character, you can choose a replacement for any or all of your alters, if it makes sense. You can also work with your storyteller to change an alter wholesale due to some supernatural effect or immense personal change. Between these two options, your alters can grow more differentiated over time, develop similarities to each other, etc. as you see fit. Newly created alters don't get these extra specializations retroactively.