Mayu (formerly called Tomone) is a character in the anime/manga series Noragami. She is a Regalia who currently serves Tenjin, the God of Learning. Previously, she served Yato for three months, until she grew tired and quit, leaving him defenceless until he found Yukine.
Despite their rather rocky relationship, Mayu has shown time and time again that she cares for Yato a lot more than she lets on. An example would be when she agreed to take part in an ablution in order to cleanse him and Yukine.
She is voiced by Asami Irai in the Japanese version of the anime and Leah Clark in the English version.