Miyako is a Mana priestess; She provides assistance to Howard by guiding him with her voice.
In the first chapter, she is about to be sacrificed along with Yukie. This is witnessed by Melissa Gale and Sol Jackson? as Howard Wright interrupts the ritual, making it possible for Miyako to escape.
Miyako is mostly seen with Howard Wright. She mixes her blood with Howard's? making him immune to the shibito infection. It results in her stating "You were untainted, but now...I'm sorry..."