There aren't any specific novels focusing on the Twisted Rune. However, Priamon "Frostrune" Rakesk *features* in Steven Schend's Blackstaff. Jess Lebow's Master of Chains novel -- part of THE FIGHTERS series -- features Shyressa, Runemistress of the Twisted Rune as one of the antagonists. There's also a few choice Twisted Rune tidbits included within the story itself.
Yeah, not much showcasing of these guys n gals in the novels. They show up in the Baldur's Gate 2 CRPG as well as being a main villain in some modules.