Kotaro is a very energetic and inquisitive child. Highly intelligent for his age, he refuses to remain a toddler and always appears to be nine-years-old. He thinks that it is a mature age to be, and he seems to fit the role well. He severely dislikes being called a baby and has a strong sense of devotion and a strong desire to help others. While Kotaro is well intentioned, unfortunately he is entering his terrible twos and has become a bit of a brat. Half the time he is loving and kind, but the rest of the time he is prone to anger and speaking without thinking. He also adores curry and chocolate.

Kotaro was born to Kanja, a former human turned tanuki kami by his father Yaku. He lived the first two years of his life as a naturally born tanuki kami. While on his first assignment, he met a human named Kaworu who very quickly fell in love with Kotaro. As a consequence of this, Kaworu's once hardened heart softened so much that both the demons and Okami took notice of what his special gift would be as either, and they took part in trying to court him to their side.

As a kami, he was raised to dislike demons and shinigami. As such, his relationship with Kaworu's friend Kumo was tenuous until something truly magical happened. Kotaro did something that was not typical for a child. He broke his fears when he learned that Kumo had been in love with Kaworu for almost all of Kaworu's life, and when he escaped to seek solace and think over his feelings that he couldn't display, Kotaro followed him to attempt and console him.

Unfortunately for Kotaro, being the son of Yaku who had been banned from Japan by the now former tanuki kami elder Minato, Minato wanted nothing more than for him to die. Kotaro had been temporarily made human by Abe in hopes that their relationship and bond would strengthen, to the benefit of Kaworu's heart. Minato was made aware of Kotaro's temporary humanity a few moments before he went to console Kumo, and came to try and draw him out to destroy him. At the very end, knowing that he was a human and stood no chance, he tried his best to protect Kumo. Kumo wasn't able to forgive himself for allowing Kotaro to die, even though that wasn't his fault.

As soon as Abe heard what happened, Kaworu being unaware of it, he put Kaworu into a three day sleep to see if there was anything he could do to remedy the situation. Learning that there was nothing, and feeling and expressing tears for the first time since he was a child, he returned to Kaworu, woke him up, and tried to explain what had happened as best he could. Kaworu, of course, took the news poorly and resolved to become a demon, simply so he could personally kill the Okami for not protecting Kotaro when he was at his most vulnerable. As a result he called the Dark Prince forward, but the Dark Prince had some news to provide before he would allow Kaworu to make that decision. He told Kaworu about Kotaro's intentions, and how he was never afraid. His only concern was helping Kumo if there was anyway possible. His dying hope was, "I hope that this means I don't cause anymore trouble, and maybe this means that Kumo and Kaworu can be happy together now."

When humans die for a noble deed, they become a kami. Kotaro was a human temporarily, but the rules of death for humans weren't a part of his fate. He was still bound to the same rules that kamis have. When kamis die they are allowed to see their hopes come true. However there was a minor complication with Kotaro's hopes. None of the hopes he spoke had any chance of coming true. His death had caused Kaworu a considerable amount of trouble, and Kumo would never accept Kaworu's love because he knows how much Kaworu loves Kotaro. So while he wasn't thinking of himself, his hope of not causing Kaworu trouble could only come true if he wasn't dead. So the moment that Kaworu became aware of his death and broke down, Kotaro was brought back to life as the tanuki kami he had always been.

Kaworu, at that moment, vowed to become a demon under the condition that Kotaro and Abe would become demons as well. He did this because, with Minato dead, an impending civil war between the tanuki kami and the kitsune kami was on the horizon. A civil war that Kotaro would have inevitably been drawn into and would have likely died in since he wasn't particularly gifted at combat. With all parties in agreement, all three became demons.

Kotaro is a rather rare demon. He gained the pale skin that they all have, but his eyes remained their natural blue instead of turning red.

Art by MonochromeAgent