Edit: I had the wrong spell earlier. I thought it was Charm Person. I hope this doesn't make it a moot question, just because Charm is more severe.
This happened long ago in our campaign, but I've been wanting to ask about this scenario anyway.
My party fought a great vampire lord who tried to take over the continent. After a huge battle we captured him and he used Charm on my character to aid his escape, which I failed to save against. Despite this I said that I try to stop the vampire lord from escaping anyway, but the DM wanted me to defend the vampire lord as he escaped and other players around the table (some more experienced in DnD than myself) agreed with him saying that my character sees the vampire lord as a friend.
The description of Charm is as follows:
The Charmed target regards the vampire as a trusted friend to be heeded and protected. Although the target isn't under the vampire's control, it takes the vampire's requests or actions in the most favorable way it can, and it is a willing target for the vampire's bite Attack. (MM 297)
And the description of the Charmed condition is as follows:
- A charmed creature can’t Attack the charmer or target the charmer with harmful Abilities or magical effects.
- The charmer has advantage on any ability check to interact socially with the creature. (PHB 290)
The thing is that my character, while neutral good rather than lawful, believes that those who are accused of crimes should be allowed to stand trial (or forced to, if the accused doesn't want to like in this case). The spell description of Charm doesn't say that it alters memories and my character wouldn't let even his best friend evade trial knowing that he did what the vampire lord did.
I haven't specifically written this view in my character's profile, but I do believe that there's enough information to go on, as well as precedent throughout the campaign, to surmise it.
I'm not saying that the Charm spell had no effect. Without it my character would think that the evidence against the vampire lord as well as the seriousness of his crimes would be enough to warrant a summary execution (again, my character is not lawful good, so his stance can change for extreme cases like this). I wanted him to take a milder stance as the effect of the Charm Person spell. That is, make everyone agree to let the vampire lord stand trial rather than execute him, not outright try to help him escape like the DM wanted. Making the vampire lord stand trial would of course require that he doesn't escape, so reasonably my character should try to prevent that.
My question is this: Is a character's beliefs and personality argument enough to oppose (in a non-harmful way) someone who has charmed them with the Charm spell?