Just finished The Law of Nines. All I can say is...wow. What a way to conclude the Sword of Truth series. The book really answered a lot of questions left open at the end of Confessor. However, it also raised quite a few more. One in particular is: What happened to the House of Rahl? Jax made it quite clear that the Rahl line no longer existed in her world. She explains that, shortly after the war with the Imperial Order ended, history simply forgets the House of Rahl.
One interesting theory I've found is based on a portion from Stone of Tears. In SoT Richard is distraught over discovering that he is a Rahl. Kahlan suggests that, after they are married, he could take her family name (Amnell) as husbands of Confessors often do. Richard seems to like the idea but it never pans out as the series progresses.
The theory now is that, after the conclusion of Confessor, Richard in fact adopts the surname of Amnell and leaves Rahl behind him.