[quote=@Undine]
<Snipped quote by Vetis>

I would assume that the limits would be the degree of illusions.  Is the illusion based purely on sight, or can your character make people think that they're touching something when they're not?  Is there sound? Smell? Taste?  Is there a maximum amount of people who will fall prey to the illusion at a time, or is it a radius?  How accurate are these illusions?  How long do they last? How intensely will your character have to concentrate in order to cause these illusions? [url=http://powerlisting.wikia.com/wiki/Illusion_Manipulation]This link might help you with some variations and limitations.[/url]
[/quote]

an interesting thought, how about the idea that the more of the five senses the fewer people he can affect? as an example, if an illusion is created to only affect one Sense it could affect 10 people, but if it involved all 5 it could only affect like 2 people (not exact numbers, but an idea of the scale of how things might work) and a similar idea to range.