Residents of Yuragi-sou
Ouga's only disciple. Prior to their first meeting, Ouga was "rescued" by Kogarashi when she was luring a demon only for her to rescue his soul instead. Regardless, she watched over Kogarashi and made him as her disciple after witnessing him punching an evil spirit as the result of receiving her portion of her energy. During his apprenticeship under her, Ouga trained Kogarashi relentlessly to the point he managed to beat Garandou that killed her 100 years ago.
Tension between the two however arises when Ouga accuses Yuuna as a host of both Tenko and Garandou, something which Kogarashi himself denies. This didn't stop Ouga from knocking him and chasing Yuuna throughout the beach and city. After the truth was revealed and the Byakuei incident was finally resolved did Ouga apologize for her actions towards Kogarashi and Yuuna. After learning how she was Kogarashi's first love, she then confessed she loves him too. Despite her confession, Kogarashi mentioned how she said that to him many times in past. She stated that their relationship was much closer to siblings. When she realize Kogarashi was no longer in danger and he had many friends by his side, Ouga emotionally bid farewell to everyone before she finally passed on to the afterlife. Before she passed on, she hinted that Kogarashi would go through a similar level of pain and experience if anything goes wrong, and wants Yuuna to stop him in that case.
The mysterious ghost who is the resident of Yuragi Inn and also one of his disciple's room mate. Whilst accusing Yunna as the deceased Tenko Genryuusai of the Three Big Families, Ouga also accuses her as the Garandou when she hasn't saw the evil entity at the underworld, which force her to escape the realm and living the human realm for 2 years prior her pursuit for Yuuna. She was so stubborn on bringing Yunna to hell that she refused to listen anyone who claims the ghost's innocence, including even Kogarashi. Ouga is aware of Yuuna's kindness and explained its the reason she refused to back down because she feared that it will make her hesitate to destroy Yuuna. When Yuuna subdues Ouga by unlocking some of her past memories and proving her innocence by confronting the true mastermind, Byakuei Tenko, the two finally put aside their differences and became friends. Ouga went as far as apologizing to Yuuna, allowing Yuuna to wash her back, and giving the ghost sound advice that Yuuna should be more honest with Kogarashi about leaving one another before finally passing on.
Oboro was interested in Ouga for being Kogarashi's first love. However, the two became adversies when Ouga attacks Yuuna under the suspicion she is Garandou. Due to Ouga's reputation in power, the only thing Oboro could do is to send Ouga into another dimension with her Teleportation Techniques, only to see that method is useless as Ouga easily repels her powers very easily. After everything was settled, Oboro continued her interest on how Ouga was able to become Kogarashi's first love much to her surprise.
The (former) member of Yoinozaka House of the Three Big Families who currently is a member of the Yuragi Inn and a manga artist. Their feud between them is the result of Ouga's accusation against Yuuna for her identity as a Garandou. In order to protect Yuuna from Ouga's harm, Nonko drinks a lot of sake just to have a match with Ouga, something that garners her interests for as she have never fought a Yoinozaka since her death. What's beyond her expectation however is Nonko's 1000 Litter form that obliterate her Spiritual Armor with just one blast. By far, Nonko is one of few youkai to pressure Ouga despite her eventual defeat via an opening.
A Nue affiliated with the Hiougi Estate as well as an ally of Kogarashi. Due to Ouga's intimidating face, Matora presumed she wanted to fight only to be quickly defeated. After regaining consciousness, Matora would then ask the Yatahagane on how to become stronger. Under Matora's suggestion, Ouga decides to tell the Nue the location of Zakuro.
A were-wolf like youkai who is Ouga's rival that kidnapped her so he can rule over earth and beat the Three Families. It is only until Garandou's invasion that both Ouga and Zakuro were forced into working together in order to repel the more dangerous threat. After the incident they, along with Kogarashi, became very close that they traveled to various worlds defeating evil gods.
A mysterious entity that threaten the youkai realm. 100 years ago, Ouga perished during her battle against Garandou. She has a grudge against Garandou and desires to destroy it. After learning that Garandou was a technique created by Byakuei Tenko, she turns her attentions towards him.
The founder of the Tenko family. When Ouga learns how Byakuei Tenko was the mastermind behind Garandou and destruction of the Yatahagane lineage, the two became adversaries. She assists in Kogarashi's and Yuuna's fight against him. Despite his actions, she was shown to be not so spiteful towards him after learning the reason was to save his own daughter, Mahoro Tenko. She even points out the subtle hints of how the Tenko founder did cared for Yuuna. After Byakuei was finally defeated, she watch in acceptance of Byakuei and Mahoro's passing.