The Moss Prophet is found preaching about The Radiance to a group of Mossy Vagabonds in Queen's Gardens, in the early stages of the infection.
After Broken Vessel is defeated, he is found seemingly dead, completely overtaken by the infection.
Oooohhh radiant being, we are blessed. Your rays touch us. Your warmth fills us. Hallownest is born again, united in your blazing image. Oohhh...
Light is life, beaming, pure, brilliant. To stifle that light is to suppress nature. Nature suppressed distorts, plagues us. Embrace light! Achieve union! Oohh..Ahhh.
... Blinding... Rising... Never be empty...
Dream Nailed after infected
When the Knight engages the Mossy Vagabonds that sit around him, he hides, but once they are dead, he resumes singing.
Moss Prophet is the only moss creature who doesn't attack The Knight. He is also the only moss creature with normal dialogue.