The Morose Mononokean

is a Japanese manga series written and illustrated by Kiri Wazawa. An anime adaptation by Pierrot Plus aired from June to September 2016, followed by a second season (also by Pierrot Plus) thar aired from January to March 2019.

Plot
The start of Hanae Ashiya's high school life has not been easy—he has spent the first week in the infirmary, and his inexplicable condition is only getting worse. The cause of his torment is the mysterious fuzzy creature that has attached itself to him ever since stumbling upon it the day before school began.

As his health continues to decline and the creature grows in size, Hanae comes across a flyer advertising an exorcist who expels youkai. Desperate and with nothing left to lose, he calls the number and is led to the Mononokean, a tea room which suddenly appears next to the infirmary. A morose-sounding man, Haruitsuki Abeno, reluctantly helps Hanae but demands payment afterward. Much to Hanae's dismay, he cannot afford the fee and must become an employee at the Mononokean to work off his debt. And to make things worse, his new boss is actually one of his classmates. If Hanae ever hopes to settle his debt, he must work together with Abeno to guide a variety of dangerous, strange, and interesting youkai back to the Underworld.

Official

 * Official anime website