CyanideSpirte said:
I feel like the tenets "Fight the greater evil" and "By any means necessary" give a lot of freedom for the paladin to do extremely heinous things that are completely unsuitable for a paladin.
Paladins in 5e aren't the same as paladins in other editions. They can do heinous things if they want, as long as it upholds their Oath. There's nothing in the class that forbids being a massive jerk. There's nothing that even forbids being Evil or Chaotic or (gasp!) Chaotic Evil. Some of the Oaths seem to prohibit certain forms of being a massive jerk, but the Oath trumps alignment or jerkitude in the class.
In a game I ran recently, a paladin in the group went Oath of Vengeance and declared alcohol to be the greatest threat to humanity after seeing so many bar fights, abuses in families, etc, which all had alcohol in common. He went on a quest to abolish alcohol by any means necessary.
So far, a little weird, but not a problem.
During his adventures he would torture people or even use a Philter of Love to force someone to be obsessed with him for even the most vague information he could (like for information about a magic item that he rationalized MIGHT assist him in ridding the world of alcohol).
Sure. He's all
Frank Miller Batman about stuff.
I have a view of Paladins as they are described as being the archetypal heroic knights in shining armor so this does NOT sit right with me but Oath of Vengeance seems to permit some ridiculous things without penalty.
Your view of paladins is outdated as far as the RAW of 5e is concerned. If you want something closer to that knight in shining armor philosophy, look at the Oath of Devotion. If that's the only kind of paladin you want, ditch the others.
I'm not quite sure as a DM how to reign that in while giving him freedom to have his character because it made the rest of the neutral/good party members extremely uncomfortable.
Hold up a sec - it's not your job to reign him in (or the job of the rulebooks, FWIW), it's
the player's job. If the player can't come up with a reason the rest of the party should keep his character around despite his extreme methods, it's time for him to roll up a new character that CAN give the party a reason, if he wants to keep on the same storyline as the rest of the party.
If your character as conceived of can't do that, only one real reasonable reaction:
As a middle ground, if you give him some alcohol-related evil he can punish, it might at least serve to channel his energies in a party-friendly direction. Maybe there's a succubus behind a new bourbon distiller in town who plans on getting everyone drunk before summoning in some demon buddies. Maybe there's a group of hedonistic fey that come into town ready to party and cause chaos. Maybe there's a group of nefarious dwarven brewmasters who want their ale to succeed at any cost (que knife in the back of their enemies).
I might not personally do that because I don't consider a player's sociopathic character to be my problem as a DM, but if he wants to be Frank Miller's Batman, give him a Frank Miller Joker, too.