Charmer technically has 3 stuns. Cant remember all of their titles but so:
1) 5th main skill oppression which deals magic damage and at 4/4 stuns for 3-4 secs
2) expert skill with metheors animation which can be directed to 3x3 area, it deals multi damage firstly and then multi stun for 3-4 seconds, not sure about the number of targets but have to admit it was dodged many times, especially by moving targets
Sadly 1) and 2) even at 4/4 dealed low damage, possibly 70-80% of magic damage
3) The last was also expert and the magnificent one. It's similar to locks current expert skill, the difference was its size - tiny rock and that you can cast it on opponent which makes him invincible, btw at 4/4 it stuns for freaking long time 8+ seconds
That's all what I noticed about charmers stun system, maybe someone could be more accurate.