The other one-time enemy that appears in the Alfman boss battle, this girl is the partner to the Chancellor Guard.
Like the Guard, the Chancellor Reyvateil herself is very resilient too, so it will take some time to take her down. However, she is also the first target that should be downed in the battle, as her Cheer Wave skill can heal the others and thus prolong the battle unnecessarily. In this case, it would be advisable to use Song Magic to speed up the process, so the player can concentrate better in taking down Alfman.