Linking Advantage and Disadvantage

[myrmidon]

Is there a way to link an advantage and disadvantage? I was thinking of giving a player an advantage, but he would only have it as long as he kept a certain disadvantage. If he buys off, the disadvantage, the advantage would go away. I read through the Modifiers part of Advantages, and didn't see anything that would fit.

[Anaraxes]

Temporary Disadvantage (B115) would be the go-to modifier if the Disad shows up only when the ability with the Advantage is activated.

But it sounds like you're talking about a longer timescale -- character creation and development. If you want the Advantage and Disadvantage to be available only as a package deal, just package them together as a meta-trait (B262). Give it some appropriate name, add the costs together to get a net cost, and it counts as a single Advantage (if positive cost) or Disad (if negative cost), so it's not possible to buy off just the Disadvantage part.

A GM can always of course just simply require the character to buy both, and tell him (ahead of time) that the Advantage will be lost if he buys off the Disad.

[myrmidon]

I was intending for it to be longer-term, if not permanent. I will just have him take both and tell him that they are linked, as you recommended. Thanks for the advice and references, Anaraxes.

[Dingle]

There is the "temporary disadvantage" limitation. It gives the disadvantage for only the time that you are using the advantage, which may not be what you want.

The "pact" limitation is closer to what you want, but is specifically about self imposed social disadvantages.

Generally, things changing what you can and cannot spend points on are perks, quirks, or 0-point features. So the GM could just arbitrarily say that they are linked as a single meta-trait.
(I consider "unusual background" to affect the world because it relates to things that the world doesn't expect to exist)

[Kallatari]

What you are talking about - the need for having one trait before you can get another - is a prerequisite, not a link. The requirement for any prerequisites is a 0 point feature for the campaign setting, and decided solely by the GM.

It has been clearly stated that the need for a prerequisite is not a limitation (I unfortunately don't remember where... pretty sure it was a Krommsnote or FAQ, but might have been an actual RAW statement somewhere). The fact that you must spend points on another trait is not wasted points since you are effectively getting all the benefits of the prerequisite trait. The fact that you may not have wanted it does not remove the fact that you are benefiting from it. It therefore should not reduce the value of the final trait which required the prerequisite(s). Think of it as it shouldn't cost any less (or more) than someone who has both traits independently, since mechanically they work identically. A limitation is only worth points if somehow, mechanically, the trait is more limited.

While that statement was made with respect to different advantages as prerequisites to each other, the logic still applies for disadvantages. The fact that you get points back for the disadvantage that is a prerequisite means that the disadvantage affects you, whether you wanted it or not, and therefore shouldn't affect the cost of the advantage you want to get. You did, after all, get the points back for the disadvantage, just like everyone with that disadvantage would.

The Pact limitation is a special case. The main difference is that Pact is not about requiring a prerequisite disadvantage, but about the fact that you must meet the "behavior" of a disadvantage. You get a limitation value because if you don't behave in a manner that is consistent with the disadvantage, whoever is granting you the ability will take it away from you. The advantage is therefore given to you at the whim of this entity, not because you have a disadvantage or not. Technically, you don't even need the disadvantage to have a Pact... but since you have to behave according to the disadvantage and suffer the consequences anyway, it would be rather silly not to take it. It's basically free points in such a situation. But you could technically remove the disadvantage, and not lose your Pact... although the lack of behaving accordingly is likely going to cause you trouble. Conversely, if a character with a Pact who had the actual disadvantage kept using Luck to reroll self-control rolls or organized events so that the self-control rolls never have to even come up - and thus he would never be forced to take action according to his disadvantage - while it would be a legitimate approach with respect to dealing with the disadvantage itself, the entity granting the Pact might not be so happy with him and would probably penalize him for breaking his Pact. After all, the entity can remove whatever he gives you as a Pact at his whim. The link to a disadvantage with a Pact is merely there to codifying what the entity is expecting from you.

Anaraxe's method of combining the to traits into a packaged ability is technically valid. But then I'd ask the question - if someone neutralizes the advantage, does the disadvantage also go away while the advantage is neutralized? If the answer is yes, then combining them into a single ability as a package makes perfect sense. If the answer is no - you would still have the disadvantage if the advantage was taken away, then I'd argue that having the disadvantage as a prerequisite to the advantage is the way to go.

Example of a Package: Having psionic powers also makes you crazy. If someone cures your craziness, the psionics goes away while you remain sane. Conversely, if someone drains away your psionic powers, you will regain sanity while they are away.

Example of Prerequisites: Only those who are insane are capable of using psionics. If someone cures his insanity, he loses his psionic powers. If someone drains his psionic powers away, however, he still remains insane.

Either way, they are both 0-point features, and available (or not) at the GM's discretion for his campaign.

Edit: As mentioned by others, a Temporary Disadvantage limitation means the disadvantage only applies while the advantage is being used. So with the psionic example, you would only be insane while your psionic powers are active, but would regain sanity when you turn them off.