I've been watching a discussion on a thread in DF regarding the "Charm Person" spell for a couple days now. I've chipped in a couple times in response to a question but I have been otherwise just reading with interest many of the responses, some of which seem, to me, to take such a first level spell WAAAAY overboard.
I can see how people can abuse such a spell just as I can see how easy it is to get carried away with it.
Here's my take on the spell.
It gives the caster about the same influence over a target that a person the target puts on a pedestal like someone they are a fan of or that they idolize. They will do just about anything (within certain parameters) to impress the caster as they would their idol. If that idol should let them down, seriously disappoint them, bring them to harm, etc... the person "opens their eyes" so to speak and just like in the spell, it is over.
It's not meant to be a total mind control spell. it won't let you turn the target into your slave or robot.
Someone brought up the difference between the effect of Charm that a monster such as a vampire casts on victims and the Charm Person spell and I agree, the monster's version is more like that of a cult leaders influence. It's akin to being brainwashed instead of being "star struck".
There is already a spell that gives more influence to a caster in the third level spell, "Suggestion" which is more like the Jedi mind control Obi Wan uses to cause people to think, "These are not the droids you're looking for."
Does the target "know" they have been placed under a spell while it is occurring? I think that depends on the situation where the DM has to decide if the circumstances are so contrary or out of normal for the person to question their own "thoughts", otherwise, probably not.
Will the target, if they realize they are actually a spell target, be unhappy about that? I think that's a stupid question. The caster in question better have some options at hand just in case such a target snaps out of their control.
How long will the target stay under the spell? According to the spell, so long as they keep failing anticipated savings throws, indefinitely. The more intelligent the target, the less likely they will stay "Charmed", again, based on the saving throw schedule.
Can you use the charmed person/monster as a solider/bodyguard? That depends on the nature of the target to begin with. If they are not a fighter type to begin with and the request is not phrased just so, then highly doubtful.
If they are a fighter type personality and the caster couches the request in such a way that makes sense to the target, then probably so. You'd pretty much have to make it seem like it was their idea, seeing as it can directly place the target in danger.
Are said charmed targets the same as a henchman? Do they count against the henchman limits of CHA? Personally, I'd say no. It's not a "Create Henchman" spell. The point of the spell is to make someone friendly to you without having to take the time to build a friendship. I see this spell more as something to help you get into a restricted access area or to get help finding something or someone, etc...
I see "Charm Person" as part of a Role Players game rather than in a Chess Masters game in that the real use and fun of using such a spell is based on the role playing interaction with the NPC's and other PC's encountered.