Shirogane

Shirogane (シロガネ, Shirogane) is a powerful ayakashi and the former king of the ayakashi. He is after Suzu Kanade, wanting to consume her to increase his power. After his original form was sealed, he would become Suzu's cat helping her find a way to reverse the body-switching seal placed on Matsuri Kazamaki.

Appearance
In his small form, he is a normal chubby white cat with ayakashi curls on his tail and ears. In this true form, he grows in size and becomes more vicious looking. Also, in his visible form he looks like an ordinary chubby white cat without ayakashi curls and can be seen by ordinary humans. After being injured by Une, Shirogane would merge with Suzu, gaining Suzu's appearance but retaining his cat personality. In this form, Suzu would gain the appearance of a cat by turning her hair white and gaining ears. Upon discovering that his injuries have not been fully healed, he decides to make a deal with Kanade by fusing with her, in this form Shirogane obtains the form of Kanade having the same characteristics as the fusion with Suzu, but being able to be invisible to people.

Personality
Shirogane is a proud ayakashi due to being one of the strongest ayakashis due to the fear humans had of him. Over time this fear was disappearing making Shirogane feel replaced. He has contempt for couples because he finds it unpleasant. After being locked up in his small form, Shirogane begins to behave like a normal cat.

Plot
Shirogane observes Suzu Kanade, realizing she is a Ayakashi Medium and plans on eat her, but Matsuri Kazamaki shows up and stops him. As Suzu notices and saves Shirogane from Matsuri, commenting that Shirogane is just a harmless ayakashi. While spending time with her, Shirogane eventually reveals that Suzu is an Ayakashi Medium and that's why Matsuri is always protecting her. He turns to his original form, revealing to be the King of Ayakashi and attempts to eat her, but Matsuri comes in and starts fighting him. Matsuri manages to use a scroll, sealing most of Shirogane's spiritual energy, but Shirogane manages to use a gender reverse jutsu, turning Matsuri into a girl and then managing to escape in a weakened state.

Later he goes to Matsuri proposing that he return his energy and he will turn him back to guy, and states that he isn't interested in Suzu anymore, but as he drools, Matsuri realizes he is lying. Shirogane then calls an ayakashi he released from a seal, but as it doesn't show up, he realizes he may have been after Suzu, but Matsuri reaches her in time and saves her from the ayakashi. Shirogane then decides to transform into Suzu and goes to the bath window of Matsuri, while he takes a shower and wonders about the scroll. As Matsuri reveals he always keeps it, Shirogane transforms into cat and takes it, but is again caught by Matsuri, who decides he needs to exorcise him, even if he would remain a girl forever. Suzu shows up and stops him, having no choice, Matsuri decides to take Shirogane as a pet.

Suzu Kanade
At first, Shirogane wanted to eat Suzu due to her spiritual power, but after his plans are thwarted by Matsuri he is forced to act as Suzu's cat. Over time Shirogane and Suzu have had a good relationship with Suzu being one of the most important people for Shirogane.

Matsuri Kazamaki
Being the culprit of making Matsuri become a woman, Shirogane and he did not have a good relationship at first, this was left over time as Shirogane and Matsuri became friends.

Kanade
Although at first they had no relationship, it wouldn't be until Shirogane was injured that they would both have a conversation, Kanade would heal Shirogane's injuries and she would take his body in exchange. Although both were not used to being together, they resolved it until they reached a balance for both of them.

Trivia

 * He can get drunk on catnip.