Calamus is one of two children residing in the ruins, the other being his younger sister, Alula. He's a teen with tan skin, short but messy maroon hair resembling a bird's face (eyes and beak) casting a shadow over the top half of his face, circular white eyes visible from the shadow. A single red feather sticks out from the back. He wears a long shirt with patterns similar to that of a poncho and bears the symbol of the Sun. Much like other Bird People, his arms are covered with feathers, his hands appear to be gloved, and he has bird legs.
Not much is known about his background except regarding his family. His father, Rachis, was friends with the Author and for an unknown reason became absent. Calamus, Alula, and their mother lived in the ruins for a time. When their mother passed away, Calamus took the responsibility to look after Alula.
Calamus is a kind, sensitive, and anxious character. Evidenced by his care and protectiveness over his sister, mild shame when he did not address Niko as the Messiah during their first encounter, and his reaction upon Alula disappearing.
- Calamus' name comes from a term in zoology which indicates the hollow, base portion of a feather. 
- According to Nightmargin, Calamus is a teenager.
- For Solstice Day, Calamus received a book from the Author as a gift. He expresses that he wants to continue studying it, as he hasn't yet finished reading it.