Okay, so I gathered that you can convince Balthazar to help you against Melissan if you have enough wisdom.

My question is: How much do you need?

I think you need 18 WIS and 15 CHA, but I'm not sure.

Are Wisdom and Charisma requirements? I always thought it was based on your alignment. If you're good, and take the right dialogue choices, Balthazar will help you out. If you're evil he won't.

I'm pretty sure I would have spoken to Balty (cant br arsed to spell his name) with a Wis 18 and Cha 15 and not been able to persuade him to even make me a cuppa tea. Anyone confirm?

Stats aside, how about alignment indeed? I can see him refusing an evil person, and helping a good one...

How about a neutral character? And does Chaotic vs Lawful play a role in it?

I can't remember for sure, but I think I got his help with a chaotic good charater. My reputation/virtue was 20 though, and I had enough wisdom and charisma, and I must have chosen the right dialogue options.

I'm even less sure, but I think I got his help with a similar character, but true neutral. Or she was supposed to be; I can't remember what her alignment was by that stage, if Virtue changed it at all. She had enough wisdom and charisma at the time as well.

Is this with a mod? I've talked to him with wise characters like Morsmordre did and I've gotten no help either.

It's an Ascension feature. Unmodded Balthazar will fight your party regardless.

You need 18 rep and 15 (at least) in wisdom and charisma. I believe that even higher wisdom will give you a better chance to get him to join, but 15 is the minimum. Evil characters can convince Balthazar to join as well, though the requirements are even higher.

It's with the Ascension mod. He won't join you in the original game no matter what dialogue choices you make.

In Ascension, if you're a good character you can persuade him to follow you and fight against the Five and Melissan. If you're evil he won't join no matter what you say or do, but on the plus side you can recruit Bodhi to your side.

*nodnod* I was talking about with Ascension installed. Being able to recruit him was one of the main reasons why I got Ascension in the first place: it made better sense, than only ever fighting him no matter what.