WereCat series by Sakyo Aya:
http://www.mangago.me/home/mangalist/119876/
Kokonoe is a werecat who turns into a cat when he is excited. Destiny has it that one morning, Kokonoe, runs into the school doctor Natsume, who seems to have a special relationship with cats. With Natsume's touch, Kokonoe soons finds himself purring and getting excited. However, Kokonoe is determined to keep his cat side and the feelings he has for Natsume under control.
Part of the Warui series:
http://www.mangago.me/home/mangalist/119514/
1. Mujihi Na Otoko - 2. Mujihi Na Anata - 3. Mujihi Na Karada
Nanao Shirahane is notorious for being a male siren, able to lure in and 'slay' any man simply upon his will. And while these rumors hold no truth, Kuon Aikawa, a fellow student attending the same university, still can’t help believing them and despising Nanao along with it.
Part of the Warui series - Nanao & Kuon's arc:
1. Mujihi Na Otoko - 2. Mujihi Na Anata - 3. Mujihi Na Karada
While on a trip with Kuon, Nanao runs into Kiriya, his old senpai from high school. Drama unfolds as Kuon does whatever he can to keep them from seeing each other.
Part of the Warui series - Nanao & Kuon's arc:
1. Mujihi Na Otoko - 2. Mujihi Na Anata - 3. Mujihi Na Karada
Upon hearing rumors of Kuon's ex-girlfriend, Naono starts having doubts about their relationship. One night he gets drunk and wakes up in Professor Satonaka's bed!
Part of the Warui series
Features former student council president, Shiro Akagi (Mikado's rival in Warui Koibito and Warui Oujii) and disciplinary committee member, Nao Kousaka (Yukimura's rival in Sunao ja Nai Kedo). How will those two damaged people find their respective love?
On a hot summer afternoon, Hayato meets the new transfer student name Souma, who has not been able to adapt to the new environment. Hayato always manages to be in Souma's sight, and thinks he will be able to take care of him. The familiar touch allows Souma to familiarize with the environment, until he's able to smile once more. All the while Hayato tries to fix things from his past.
1-3) Bi no Isu
Kabu and Nirasawa have a troubled relationship, to say the least. Harsh yakuza lifestyle, torture, and violent sex are everyday occurrences for the volatile couple.
Sequel to: Bi no Isu
Kabu was told by his father, that he is going to succeed the Umezaki group, but he is hesitant to do so. On the other hand, Sagawa, who is regarded as the successor of the group by everyone else, tests Kabu’s loyalty by giving him an ultimatum, to give up his company or Nirasawa. For Kabu, Nirasawa is not only a convenient pawn, but at the same time he’s a lover, that has captivated him with his unexpected cuteness. Will Kabu really send Nirasawa away..?!
Sequel to: Kobi No Kyoujin
Kabu has finally succeeded his father, but with Shao Chen still alive and out to destroy the Umezaki group, the situation around Nirasawa and Kabu is heating up.
Riku suffered a traumatizing experience after coming out and has since chosen to avoid love. That is until the super-confident and dominating pretty-boy, Yoshimi, walks into his life. He deliberately targets Riku's weaknesses, but what are his true intentions?
Nekoka Kareshi No Ayashikata