I want to play a pure illusionist that is scared of battles and relies on illusions to survive. But, I'm really don't know how to go about this. Because I never did it, but aren't undead immune to illusion until you get a high level perk?

So how do you even get through the first quest to get the dragonstone? Half the people there are undead.

That's a really intriguing and unique character idea. Very nice. Unfortunately I don't know how to help you but I just wanted to comment on it.

My only thought is to get a bodyguard, follower, and keep casting brave on them as I ran and hide like a wimp.

Look up a pc gamer series called an illusionist in skyrim. The author basically forced himself to use only illusion for the entire game. I haven't read all of it but it sounds like what you're looking for.

Any particular followers you have in mind for the job?

Probably Jenassa at first. She's the first sword for hire type. More bodyguard than befriending like Fendal, which is like asking someone you did a favor for to die for you.

Like, this guy is going to be useless other than illusion. No armor, no weapons.

I'm thinking of maybe letting him have a dagger? What's so cowardly....like pacify someone and then slitting their throat. Cowards have no honor.

You can also help them by healing them. Or are you going pure Illusion even without Restoration?

Hm, I don't think Restoration is a bad idea. It's not offensive. I could probably do that.

Glad to be of help. Now go get 'em, you coward! Lmao!!