I am wondering how both society in general and the player group in particular can deal with an overpowered evil or at least hostile caster. While our group kills during the fight, they don't want to kill someone who is more or less defenceless at that moment. But just setting them free after questioning is also not a viable option.
Also, concerning the general society I don't find the idea of a prison where a large group of high level caster cast Antimagic Field hourly plausible. Are there any other ways to suppress or remove the ability to manipulate the Weave beside killing or severely maiming?
If you have ideas or references to official descriptions, I'd appreciate it. The setting is Forgotten Realms (Sword Coast).