Who is Tylwyth Waff from Heretics of Dune and what is their importance?

Tylwyth Waff is the Tleilaxu Mahai and Master of Masters. He presides over a council of nine counselors and convinces them that the "Atreides Manifesto" supports the Great Belief and will weaken all rival religions in the universe. Waff later meets an Honored Matre on a neutral Ixian no-ship, is shocked by her ability to read his mind. He kills her with concealed darts and orders the no-ship blown up with no survivors.