In Chinese mythology, the Menshen (門神) are a pair of guardian deities that protect the occupants of buildings from demons and bad omens. They’re most commonly depicted as brothers named Yù Lěi (鬱壘), and Shén Tú (神荼).
Yu Lei’s name is comprised of the characters for “melancholy,” yù (鬱), and “fortress,” lěi (壘), while his brother’s name is composed of the word for “god,” shén (神), and a character unique to his name, tú (荼). They were a fearsome pair of guardians who will throw evil spirits and demons to their pet tigers.
The Menshen are mentioned in both The Journey to the West and The Classic of Mountains and Seas. Although Yu Lei and Shen Tu are the original Menshen, Zhong Kui (鍾馗) is also frequently used as a door guardian. Their likenesses are often painted on the thresholds of buildings like temples or houses.