Hyakki Yakosho is a shojo manga from 1995. It's a lot like natsume youjinchou, dealing with ghost and youkai. It tells the story of high school student Ritsu Iijima who has the power to see and communicate with youkai and ghosts, he inherited his ability from his late grandfather... He helps those in need, both youkai and humans. He is kind and loves with his cousin a university student. His mom a housemaker and his dragon youkai bodygard who resides in the body of his late father playing the nyanko sensei role.. I loved the stories, just like natsume youjinchou, they're sad, meaningful, teaches about life and death,relationship between youkai and humans, the living and the ghosts.. some stories are also funny and light hearted.
The comedy is provided by ritsu's two youkai assistants. They are two Tengu, but appear as black and white sparrows to those who don't have spiritual powers. Their constant bickering, shenanigans are somehow tolerated by ritsu but get on his nervrs.
Sadly there's no anime but there is a live action of the same name..

English name Tales of Night-Prowling Ghosts..