Strength Kensai magus with AC 22, 121 hit points with no Shocking Grasp or Frostbite tricks. He will use shocking grasp as a damaging spell but it is not optimized (straight 5d6 only). With Samsaran cheese he has dimension door as a third level spell and with the dimensional line of feats will try to do the Nightcrawler bouncing teleport attack thing on them.
What I need to know is if you think the party will have a chance against him or not. This is the largest group I have GM'd for and I'm a little out of my element. I am aiming for a challenging fight without killing anyone (that doesn't do something stupid anyway).
How is the group setup?
Single high level powerful beings don't tend to make very even battles with large numbers of low level characters. Typically, the powerful creature kills multiple enemies per round given the chance, but is usually overwhelmed by the action economy and runs out of hit points very fast. Either that or they have such high AC and saves that the low level characters can't harm them at all.
It sounds like you've balanced him such that he won't slaughter the players too quickly. I'd suggest boosting his AC and HP a little further (or use Stoneskin) so he doesn't go down too fast if he's going up against remotely optimized martial characters. At level 5, they should be hitting AC 22 at least 50% of the time. If those nine players can do an average of 14 points of damage each in the first round, the battle will be over immediately.
Accidently double posted this. Please see the other post.