You play as a young devil who after being fed up with the demon world chooses to live in the human world, working a day-to-day job as a store clerk. After failing to read the Terms and Services of a mysterious email, a mysterious succubus named Mona appears, declaring you a contestant in the Archfiend Contest to be the new King of Devils.
This game provides examples of:
- Arbitrary Headcount Limit: You can only bring in 5 Childs, with a backup Child from your friends list.
- Battle Strip: When a Demon disguises themself as a human, they will almost always appear in a much more revealing outfit when confronted about their true forms before fighting.
- Boobs-and-Butt Pose: Along with quite a few female examples, the male Rudolph also has this as his pose.
- Bowdlerization: Several childs have had their designs modified for regions outside of Korea to be less risque.
- Eldritch Abomination: Gomorrah and Hydra are both particularly gruesome cases of this with a case of Was Once a Man.
- Full-Frontal Assault: The Azure Night skin for Olga gives him an appearance that resembles his pactmaker with some of his monstrous features. He's also completely nude.
- Idol Singer:
- Love Potion: Of the "Love at First Sight" variety. Sytry attempts this on the young master with laced chocolates, he realizes her ploy and doesn't eat them. Frej, however, ends up seeing Thoth after consuming them.
- Meaningful Name: All Childs are Named After Somebody Famous or from mythology, and their names are always based on their personalities or traits.
- One Steve Limit: Averted with Mars (Water Defender) and Mars♥ (Dark Attacker).
- Sinister Minister: Father Babila is a demon disguised as a priest.
- Stalker with a Crush: Freesia and her pactmaker are this to Hestia and her pactmaker.
- Stringy-Haired Ghost Girl: Unknown seems to be partially inspired by this, which her face being obscured when she attacks.
- Timed Mission: All battles last 5 minutes or less.
- Unusually Uninteresting Sight:
- It's made clear that anyone would be able to see Childs and Demons, but no one ever really seems too concerned about encountering some other than Yu Kano.
- Similarly, no humans ever seem to bring up the fact that the main character has a cat's tail.
- Villain Decay: Frej is an extremely rapid case of this, only antagonizing the young master for a few stages before seemingly ending up in a permanent Enemy Mine situation with him. He and Neamhain even burst into his room several times without anyone (other than the young master) complaining or protesting.