Ok, let me briefly explain how I run illusions in my game - players are completely unaware of illusions on them. I have their Resolve written down and roll against it on the sly so that they react to the illusions in the same way their characters do - believing it’s real.
An illusory sword will do the exact same thing as a physical sword because the character’s mind makes it real. Even when someone becomes consciously aware of the illusions, they must still roll against it (like any other bane) which represents their subconscious also overcoming the effects. Failing their roll, even if they know in game, that it’s an illusion means that their subconscious still believes (or fears) that what it’s seeing is real and the PC is still subject to treating the illusion as a real thing.
So, with that out of the way, as the GM, knowing 100% of the time when my PCs are using illusions - when should I allow my NPCs to ‘realise’ that they’re under an illusory effect and roll against it? I find this a hard thing to judge for myself.
Should NPCs who have never encountered illusions before just never figure it out? Should I have them do a learning/perception roll of some kind to first figure out/notice that it’s an illusion before they can then attempt to resist it?
I second what @reddevil says. I run a game with an illusionist PC, and NPCs roll whenever the illusion strains belief or is directly interacted with. Spectre’s favourite gambit is to open fights by causing the most dangerous enemies to hallucinate that something horrific is happening to them; Spectre is very good at simulating that sort of thing (Potent Bane) but the suddenness and directness of the illusion causes resists instantly and every turn. If she did something more subtle, like using Phantasm to create another copy of her already unpredictable teleporting ally, then the resist roll doesn’t happen until they have a chance to interact directly.
I think this might be a bit inconsistent for my rules, as I run illusions as if the mind completely believes that it’s real until a successful resist roll is made (even if the character has conscious knowledge of the illusion, the resist roll represents them overcoming what their senses are telling them) so physically touching an illusion would be the same as physically touching a real version of that object.
This makes sense to me though I think it would be specific to each NPC and how familiar they are with magic.
This has all been sparked by something that happened in our last game. One of the PC’s was confronted by 10 horsemen, he instantly cast an illusion of four walls appearing around them to trap them in place while he made an escape.
Without thinking, I instantly rolled resists for them all - I was more concerned with tracking each one accurately that I didn’t stop to think whether they’d know whether it was an illusion or not. I’ve been going over it in my mind since and I’m not sure whether that was unfair or not.
If I had done that to my PCs I woudn’t have told them it’s an illusion because their characters wouldn’t know, they’d have to deduce it either in game or as players then make their resist rolls.
It’s always your prerogative as the GM, but be cautious of making it too hard to resist or Phantasm will become the Uber-bane, capable of achieving a permanent version any effect that can be justified in a way that’s not totally unbelievable. If a wall encircling your 10 horsemen appearing out of nowhere doesn’t meet your threshold for “Hmm, could be an illusion” then you’re essentially giving your illusionist player license to do almost anything to any enemy provided they’re not specialists in illusion themselves. This makes it 1) very hard to balance encounters, because you can be reasonably sure that the majority of your NPCs will be unable to participate in the beginning of the fight and 2) feels bad for your non-illusionist players because this one PC is able to do almost anything.
Don’t worry too much about fairness between players and the GM, you’re not held to the same rules as them and they usually won’t expect you to be; have a talk with them if you’re concerned about this feeling. The thing you should always be concerned about is fairness between players, for the reasons I mentioned above you should be careful not to boost the strength of an already very strong and versatile build or it will lead to either everyone migrating towards that build, or bad feelings from those who don’t.
touching the wall is the perfect time for a resist roll. If they make it they would know its fake. if they fail it they touch it and believe its real assuming it has the touch portion of the bane as not all illusions have that if i remember correctly.
Sorry this is a late reply, I’ve been away from the forums for a while.
The point of this is that I don’t want my players to know out of character that it’s an illusion until they have an in game reason to doubt it - so they and their characters realise at the same time.
In my opinion if a character touches an illusory wall that has beat their resolve and has the touch property then they fully perceive and believe it to be real - so why would that trigger a resist roll?
Ok so I see your point there if they failed their resolve. I am ok with that, if it was causing harm some how I would disagree with you. It maybe best to decide case by case when its best to make resist rolls.