The story begins with the classic scenario where Naruto is chased by villagers on his birthday, only for something strange to guide him to an abandoned, creepy-looking house, where he discovers that its supposed owner is an ancient shadow demon called Obscuro. He takes the young Uzumaki in and offers to teach him ancient ritual magic the likes of which no one in the elemental nations has seen in over a century or two.
Naruto accepts this offer, but as the story unfolds, he finds that the promises of power lead to darkness and blood at every turn, so the question becomes: When he delves deep into the abyss, will he still remember who he is?
- Casting a Shadow: Obscuro can control all shadows within a certain range of his presence. He can also use them to teleport from one place to another (unless water is involved), or even "see" and feel others through them.
- Hell Seeker: Obscuro, although in a broader sense. Rather than seeking hell, he seeks the existence of an afterlife.
- Human Disguise: Obscuro possesses the power to shapeshift into other humans by absorbing their blood, although he can only do this for a short while - with the exception of his default human form, of course.
- Memento Mori: The focus of Kurama's speech to Naruto in the chapter with the same name: all humans eventually die, no matter who they were in life.
- Ritual Magic: The type of magic that is focused on in the story. It is based on old hermetical rituals and Middle Age demonic contracts. Naruto uses his life-force to activate the Ritual Circle that he draws, and each circle has different effects depending on what symbols are drawn onto it.
- Teleportation Sickness: Ajisai goes through this when they leave to the port town. Naruto does mention that the first time can be rather nauseating.