How exactly does the Concentrate trait affect gameplay?

[Auridan]

I've just started my very first game in SF2 after studying the system for months and running a portion of Dead Suns in SF1. My background is in the World's Most Popular, so naturally I have a lot of old habits to pack away. Can someone check that I have this correct, and fill in what I might have missed?

I'm playing a mystic, so I'll be needing to Sustain spells using the Sustain 1-action. As I understand it, if the Sustain action is disrupted, I lose the spell. Sustain does not have the Manipulate or Move traits, so it doesn't trigger Reactive Strike. The only trait it does have is Concentrate.

Questions are:
- Is there anything that targets the Concentrate trait that I've missed?
- What does Concentrate actually do, mechanically? Am I limited to one ongoing Concentrate at a time?
- What common actions or reactions specifically target and disrupt Sustain, if any?

EDIT: With a little more Ctrl+F magic, I've found stuff like the Anomaly witchwarper's quantum field, but I'm looking for anything that's more broadly available than a class feature.

[Milo v3]

It mainly exists to prevent you from doing stuff like barbarian rage + casting without jumping through hoops.

Also can't do concentration actions when fascinated.

[Justnobodyfqwl]

Concentrate is one of those tags that does nothing by itself, but other features care about. It's like the mental equivalent of Manipulate: it's a way to say "this is a little complicated to do in combat, so some features can make it hard to do this". The same way that Manipulate is usually on physical actions, Concentrate is usually on mental stuff. This means that stuff that's aimed at disrupting spellcasting will usually target "concentrate actions".

You're also right to notice that there aren't a lot of "universal" ways of interacting with it or sustaining spells- there's no equivalent to some other d20 rpgs and their rules about spellcasters needing to "maintain concentration" when hit. You're also not limited to "an ongoing concentration" or anything like that, so don't think of the similar mechanics from other d20 rpgs at all.

[Finoan]

Agreeing with the others here. The Concentrate trait doesn't do anything on its own. At most, it means that you might describe your character as concentrating in some way while doing the action.

So no, there is no requirement about only having one effect with the Concentrate trait active at a time, or being required to make a check of any sort during the course of the effect.

Not on its own, anyway.

What it is, is a categorization tool. New abilities that get printed can have the Concentrate trait on them, and new abilities that interact with the Concentrate trait will interact with all of those existing Concentrate actions as well as anything in the future. It prevents having to constantly re-publish an exhaustive list of every action that every ability interacts with.

Starfinder doesn't have much that interacts with the Concentrate trait yet. There are things in Pathfinder that do, such as the consumable Brine Dragon Scale talisman or the Nagaji: Disruptive Stare ancestry feat.

[Lightning Sentinel]

There is also some late game monsters that have an enhanced reactive strike that lets them use it against concentrate actions, but I don't know if there's any in SF yet. There's also the fighter's Disruptive Stance feat, also from pathfinder. but yeah, everyone else put it well.

[LeoChance]

Auridan wrote:

I've just started my very first game in SF2 after studying the system for months and running a portion of Dead Suns in SF1. My background is in the World's Most Popular, so naturally I have a lot of old habits to pack away. Can someone check that I have this correct, and fill in what I might have missed?

I'm playing a mystic, so I'll be needing to Sustain spells using the Sustain 1-action. As I understand it, if the Sustain action is disrupted, I lose the spell Among Us. Sustain does not have the Manipulate or Move traits, so it doesn't trigger Reactive Strike. The only trait it does have is Concentrate.

Questions are:
- Is there anything that targets the Concentrate trait that I've missed?
- What does Concentrate actually do, mechanically? Am I limited to one ongoing Concentrate at a time?
- What common actions or reactions specifically target and disrupt Sustain, if any?

EDIT: With a little more Ctrl+F magic, I've found stuff like the Anomaly witchwarper's quantum field, but I'm looking for anything that's more broadly available than a class feature.

No. Unlike 5e's "Concentration", there is no limit to how many Concentrate actions or sustained spells you can have active at once (other than your actual action economy). If you have the actions to spare (and ways to sustain them, like the Effortless Sustaining feat or similar high-level abilities), you can absolutely sustain multiple spells simultaneously.