I am planning on having one of my players mortal enemy be a Rakshasa. He is a major player in the kings navy, though the king does not know he is a Rakshasa. I have a decently sized group of level 7 party with a possibility of getting to level 8 before they fight him. What are some minions to throw with the rakshasa? Obviously his sailors and commanders, but what are some other fun minions he can have in disguise?

What are some ideas for the Rakshasa to really mess with the payers? How can i best use his ability to read minds?

How would you rule his magic immunity? I think I am leaning towards full immunity from any magic effect, including summons, conjuration magic, and buffs. So if you cast shillelagh on your staff, it just fails to hurt the Rakshasa like you think it would. The one thing that gets around this are buffs from good clerics, such as bless and the like, though I don't have good clerics, so this won't matter.