The Choirmaster casts all of his spells from his Book of Psalms, each spell takes one action. The book can be picked up and used by the players, with each member of the party being considered a member of this new Choir. The book must be attuned to a spell caster. A spell caster can only cast from the book 3 times a day.

At will: Screeching Falsetto-Each member deals 1D6+PL/2 psychic damage to each enemy within 5 ft and half damage on a successful Int save.   Lamentation of the Sun-Each member of the choir produces 5 ft of darkness around them.   Sweet Lullaby-Each enemy within 5 ft of a member must succeed a Cha save or be put to sleep until the end of its next turn.   Dolorous Drone-Each enemy within 5 ft of a member must succeed a Wis Save or become immobile for 4 turns, repeating the save every turn.   Plaguing Earworm-Each enemy within 5 ft of a member must succeed a Con save or take PLD4+2 Damage and be poisoned for 4 turns, repeating the save every turn.