Star Wars Knights of the Old Republic II Tips

Evil Allies
Spoilers Alert.

You can have every ally (except Hanharr, Mandalore, and the droids) become a Jedi - or a Dark Jedi. Atton is easy. Just keep him in the party and kill people. It works pretty well. After you talk to the two Twi'leks on Nar Shadaa in the Refugee Sector (the ones who tell you about Atton), you can confront him on it. Make sure not to use [Force Persuade] on him, and tell him he's an asset. If you have a high enough influence with him, you can turn him.

Visas is already evil, so just keep getting your influence with her (kill people and be nice to her).

Handmaiden: spar with her and be kind to her. Be evil to everyone else, but don't have her in your party when you do. After the last sparring match (if you win), you can turn her.

Bao-Dur: Become evil. Very evil. Keep him in your party and lose influence with him - lose it all. Kill people, shoot him down, etc. Eventually, he will talk to you about how you tick him off and such. Follow the dialogue telling him to harness his anger. You can turn him into a Dark Jedi.

Disciple: This one is harder. You can only turn him if you are a very dark side character. But, you have to gain influence with him by doing good things. Have him in your party, do good things, get his influence, then take him out of your party and perform evil things to get back the Dark Side Points. Then talk to him with your high influence, get him to talk about his time at the Jedi Temple. You can turn him evil, only if you are at least halfway down the Dark Side path. This works even better if you have a Sith prestige class.

Mira: The same as with Disciple, but even worse: you have to be have more LS points than DS when you finish Nar Shaddaa, or you won't even get this character. But once you have her, you can get all your influence through dialogue. Just talk to her, be nice to her, then go kill a lot of people while she's not in the party. Then, take her back to Nar Shaddaa, have her in your party, go to the center area (where Kreia talks to you about the energy of Nar Shaddaa). Here you can turn Mira into a Jedi - or, if you are very evil - into a Dark Jedi.

Allies that you cannot turned into dark jedi: Kreia, Mandalore, Hanharr, T3M4, HK-47, G0-T0.

Kreia cannot be turned one way or another. So don't really bother with her much. You don't really need her to get the Dark Jedi "army".

Mandalore and Hanharr are already evil, so don't worry about turning them (you can't, anyway). Just keep them evil (as if you had a choice).

HK and G0-T0 are evil, too. And, as they are droids, they obviously can't be Jedi. But still, they are evil.

T3M4 is hard to turn evil. You'll have to be very nice to him, then counter the LS points by killing people and doing bad things. When you have a high influence with him, he will automatically reflect your alignment.

There are no real bonuses for having any of your party become Jedi, or for turning them evil. But, if you want the perfect evil traveling companions - for the lack of something better to do - it's still pretty fun to pervert the minds of your "friends".