| bohzar |
I would say using dominate person, or magic, or even a changeling is weaker than giving the cohort true motivation for the assassination.
These Leadership cohorts can be exactly as you said -- fanatical. Fanaticism is extreme, and could easily lead the cohort to extreme behaviour.
Think of what a cohort would do if they believed their Leader was doomed to suffer a life of pain, shame, guilt, misery, or even torture? Wouldn't death be kinder? Wouldn't they be doing them a favour?
Or if he was convinced that his Leader was the changeling? Maybe one of your PC's hasn't been acting like themselves lately?
I agree with Kilmore, this kind of move impacts your PC a lot. In my games I have a secret GM rule to never influence the way a player plays their character. This is a big move, and should really have some clues or hints or chances for the player to become part of the situation before the daggers come out. Maybe the cohort is testing their leader beforehand? Maybe he's dropping hints of some kind? Give the PC a chance to become invested in the situation. I'll bet he does a great job of convincing the cohort to assassinate him all by himself.