Advice on using illusions in a large scale battle

[Agodeshalf]

Our party has come across a ongoing ambush between two small groups - one side is roughly 200 human soldiers, and the other a band of 80 elven archers and a small band of elven berserkers. The elves setup an ambush in the woods, and have boxed the humans in a crossfire with elves on both sides, and the beserkers on the trail in the front of the column.

We are debating about siding with one or the other and looking at swaying the outcome. We are a party of 5 5th level characters. The humans are in a bad situation, and will likely be wiped out if we do nothing. We could potentially turn the tide, if we engage the elves.

My character is a sorcerer - shadow bloodline, and have focusing on illusion spells. In any case, I'm looking for suggestions on how to make use of minor illusion/silent image to possibly aid the humans.

One idea is to put up a wall of <fill in the blank> to give the humans "cover", assuming it's believed. Another idea is to create an illusion of a drake that we've seen in the area. Another idea ...although I'm not sure you can do it is to create something like a ghost/wraith rising up from the dead humans.

Any other ideas or suggestions?

[Pizza Lord]

What you choose is incredibly important, and just as important is the spell you have available.

If you only have 1 or 2 illusion spells, you need to either be sure your viewers are going to fail to disbelieve it or only have a very limited chance to interact and thus gain a disbelief roll.

Don't make any creatures that you can't make appropriate sounds for. If you can't mimic a drake's screech (or have never seen a drake move or fight, whether you can pass a Knowledge check to know what one is), then don't try to make one. Anyone who does know such a thing would have a chance to note something wrong.

Also, if there's a chance the illusion will be attacked (especially in melee), even if you are concentrating and controlling it, the attacker will get a chance to disbelieve if they hit, because their weapon will pass through it, even if you make it start bleeding and scream. Possibly, if you're controlling it you might be able to continually have it 'dodge' out of the way, but the other side is that you have to also make it constantly miss, since any hits will also trigger saves... and do no damage (unless the illusion is somewhat real, like a shadow conjuration).

However, some GMs might allow a bit more leeway in cases where it is expected or logical. For instance, a ghost or a wraith being hit may not be enough to actually trigger a disbelieve roll (but that's all GMs call, since they are technically interacting with it). Typically, they are gonna get at least one the first time, but once they fail a GM might allow the same or similar interactions to not be noticeably strange enough to call for a check. Again, you'd still have to make the illusion react appropriately, maybe flickering out around the weapon or creating a ghostly swirl through the form of the creature.

A wall would actually be a good illusion. It would not block arrows, but would stop the elves from being able to see their targets (and vice versa).

Then it just falls on the believability of what's happened. It's probably not unknown that walls of stone or ice can appear out of thin air, and just looking at a wall won't give a check unless a creature is legitimately suspicious and then states they think it's an illusion and are trying to disbelieve it. If they succeed, they can basically see through it. If they tell everyone else, those people can make checks with a bonus, if they fail they still can't see through (Hey, magic exists, maybe the wall just let that particular arrow through because... magic. They could try and shoot or run through it). If they do actually run through it and prove it to be fake, they automatically see through it.

So, a better choice might actually be smoke or fog. This will hide the humans from the archers but if the elves shoot and the arrows pass through it (because it doesn't exist), that isn't normally considered unusual. If the berserkers rush in, they'd get checks.

The problem with this is that the humans will also be affected unless they save or somehow have it communicated that the fog is an illusion (and in a way the elves can't overhear). At least the humans will likely get first crack at disbelieving (unless your illusion has thermal, scent, or other factors), since the fog and smoke, while limiting vision, will either not feel like fog or be chilly, or smell like smoke.

For illusions, especially against multiple viewers, any one of which might just roll a 20, it's always best to limit their ability to interact with it (so they can't get a save). That means they would have to deliberately have a reason to think somethings out of the ordinary (a dragon on the horizon might or might not be).

So, stick to things that can't be directly interacted with. Ghost Sounds of horses coming through the woods and vague human voices. If speech is possible, make them human sounding like its reinforcements flanking the elves. Make fog, mist, or visual blockers (but note again, these will affect the humans). Be aware of what your illusion can't do. You can make an illusory sheet of flames that are opaque to stop vision and it also will not be suspicious if arrows pass through it, but anyone nearby (who doesn't know how the spell works) might wonder why it isn't hot, even if they don't pass through it. You could make an illusory wall of fire and anyone would knew the spell might mistakenly assume you have it facing the other way and that's why waves of heat aren't coming off... but that's a whole other mental exercise.

Sometimes, it might actually be better to use already existing items and change them. A wooden door that looks like steel might make someone opt to take a different route or a sudden bubbling pit of tar or ominous black ooze coming up from beneath the tree roots might stop the berserkers from charging since they don't believe they can (just don't have it come up where they already are standing).

Ultimately it will be up to your GM how the NPCs react and that's something we can't always predict, since we don't know how he feels about your creativity and we also can't predict what the NPCs that he's playing would know or feel about the situation (which might be different than how he feels); he could think it was an amazing illusion but it just so happens that the one elf in the blue vest happens to know for a fact that [X]... and has reason to disbelieve and gets a save... and rolls high... and conveys that it's an illusion... and the others get a bonus and pass and that's that.

[Agodeshalf]

Thanks for the response. I have minor image, silent image, and ghost sound at my disposal. We engaged with the drake in the area, so I have some experience, and it is in the area so helps with the believability. But there are obviously limitations with making a creature vs environmental effects.

How well this works is, as you say, depends greatly on the how my GM will handle how the NPCs react. So I'm hoping that I can work out a couple of plans that look promising.

So far
1) Fog/smoke which gives cover to the humans
2) Walls
3) Approaching reinforcement via ghost sound/image
4) Some ethereal creature that can be used for fear and chaos

Any other ideas?

[Firebug]

For 4) When one of the humans dies, make an illusionary Shadow pop up. Might panic the humans though...

It's incorporeal so attacks passing through it is not a disbelief check, and it doesn't sound like either side has channel energy and could start a shadow-pocolypse if it was real.

[Quixote]

Illusions have so much table variance that I would discuss a few general options with your GM.

A few other ideas: smoke or dust off in the distance to represent a more significant threat/reinforcements approaching, areas of heavy undergrowth (difficult terrain) to control enemy movement/create choke points, some elven captives you could exchange for a truce, etc.

One thing I like to do is combine real threats with illusions; there are three burning barricades. The enemy initially treats them as if they are real, so you get to control their movement.
But then your allies move through one of the barricades to attack the enemy from an unpredictable direction.
And then you have enemies wondering: are the other barricades illusions too?