A Promise -The Snake Spirit and the Nian Monster-

During an intimate moment, a snake spirit called Soukou asks Shou, a nian monster, to become his life partner. Shou decides he needs to think about it and asks for some time. Meanwhile, a tragedy befalls the nian clan after a long, exhausting history of conflict with humans. As a result, the village decides they need to relocate. Shou visits Soukou to tell him the news, but he can't quite gather the courage to tell him the most vital part. Will the two of them be separated?

(Source: Renta!)