Ayakashi no Hakobiya

Sosuke Nezuchi and Yoshiki Yoshiko work for a seemingly ordinary transport company, Mujina Transport. However, their customers are all non-humans, in other words, youkai. The reason for this is that the company is a "courier specializing in youkai"?　

What are the mysterious requests of these mysterious youkai living in secret?

(Source: Nemuki+ Comics, translated)