Seeking advice using illusions effectively

[Particle_Man]

I agree. The reason a person gets a flanking bonus, IMO, is because it forces the defender to worry about being attacked from two sides. So long as a person percieves a threat, he'll try and defend himself accordingly. This would grant the real person a flanking bonus against him.

That seems to be the philosophy with the spell in Complete Warrior that has the observer act "As if" flanked even if there is only one person engaging him in meelee. Good to use to help your rogue buddy without risking yourself overmuch.

 

[Someone]

Note that mindless opponents are immune to mind affecting effects, phantasms and patterns are noted specifically in 3.5 MM

Sure, you won´t get anything with Phantasmal Killer or Rainbow Pattern. But they are not immune to figments, and if they see one they are going to react it the same way they did the first time, even if the illusionist pulled the same trick on them a hundred times.