I have now completed the second of the books in Tanya Huff's fantasy series about the Kigh. Fifth Quarter tells the story of Vree and Bannon, brother and sister, assassins, and forced to share Vree's body when Bannon's is stolen by Gyhard, a rogue soul over 100 years old.
Maybe it was that simple after all. Maybe the bards had never needed to learn to Sing the fifth quarter because they couldn't not Sing it. Every time they touched an audience, or one listener, or one hundred, they were Singing the fifth quarter.