The human world is one of three worlds and is the realm in which humans originate from and generally reside including MC and Solomon. It is assumed that the human world in-game functions and exists in close proximity to reality with some very key differences.
Humans at large do not appear to be aware of the existence of angels nor demons, as evidenced by the fact that during the normal story-mode, angels do not make themselves known as angels, and that affecting any celestial change on a human and their life results in major repercussions and is considered taboo even among demons (such as in the case of Lilith). MC can also appear shocked at the existence of demons when they first appear in Devildom.
Witches and sorcerers are the only humans who tend to be aware of angels and demons, often through their contracts and summoning of the former.
Humans appear to be the only race that can form pacts with demons and thus command control of said demon or demons and their powers at will. MC, Solomon, and several unnamed witches are just a few of the mentioned humans to have pacts with a demon or several (as is the eventual case with MC).
- Unnamed sidewalk
- King's Cross Station
- Train car
- Unnamed bar
- Unnamed shopping district
- Unnamed bookstore
- Unnamed theatre
- Serenity Manor (the demon brothers' mansion in the human world)
- MC’s hometown
- Solomon’s hometown
- Bayside Bonanza Worlds of Wonder (a theme park)
- The backgrounds used in the Human World (particularly the train car with blue roses) mainly came from the Shall We Date game Guard Me, Sherlock.
- This game and Guard Me, Sherlock seem to share the same universe for Satan is a fan of the TV series "The Mid-Fall Murders" and the character Irene Adler.
- There are references to the Harry Potter series, which is renamed Harrison Porter in the game. Merchandise such as chocolate lizards are sold at the King's Cross Station.
- Technology in the human world is highly advanced compared to technology in the Devildom, as the brothers were unfamiliar with a slow cooker, a Roomba, and a virtual assistant similar to Alexa or Siri.
- They are familiar with appliances such as ovens, blenders, and washing machines.