I followed the law and Anomen became a Knight. But I would like to know who killed his sister, why and how I can make him pay even as a Knight?

No idea. I think it was Saerk the merchant. I'm also fairly sure the only way you can follow this up is if your main character is having a romance with him, so let's just get off the subject before I toss my cookies.

Can't do, my character is male and allready it touch with Ariel.