Loosely based on the Chinese classic novel Journey to the West.
The character PK is based on the character commonly know as Pigsy/Pig, his name in this adaptation is Pal-Kye, a play on words to sound like Porky.
The company 'Kingdom' makes an appearance when characters visit a gym. Kingdom is prominently featured in the K-drama The Master's Sun - also written by the Hong sisters.
Reunites Cha Seung-Won (Devil King) and Lee Seung-GI (Son o-gong) who previously starred together in the series You're All Surrounded (2014)