The Nine Demon Gates comprise the core members of Tartaros and, as its name implies, nine members form this team. They are very powerful as one of its members, the Devil Slayer Silver Fullbuster, was able to freeze the entire Sun Village, its giant occupants, and even the Flame Dragon Atlas Flame, alone. In another extraordinary feat, a member named Jackal singlehandedly took out the entire Magic Council, assassinating all of its members in a single raid that ended in the wounding and deaths of 119 people.
- Silver Fullbuster: An undead human Exorcist Mage who utilizes Ice Devil Slayer Magic.
- Kyôka: A Demon with distinct avian features who makes use of a body-manipulating Curse.
- Jackal: A Demon who utilizes an incredibly dangerous Curse that creates fiery and catastrophic explosions.
- Tempester: A Demon with a formerly lion-like face who utilizes a Curse that allows him to control, summon, create and fight with various natural disasters.
- Franmalth: A Demon with an armored, round body; his particular Curse involves the absorption and manipulation of souls.
- Torafuzar: A Demon with a distinct shark-like look and stern personality that makes use of his bladed arms for armed combat and a Curse that summons poisonous, lethal water.
- Ezel: A volatile Demon with an inhuman appearance, bearing four arms and six tentacles for legs. His Curse makes use of his multiple limbs, effectively turning them into swords.
- Seilah: A gold-horned, female Demon that makes use of a Curse that grants her absolute control over every person or every object.
- Keyes: A monk-like Demon with a skeletal face and a Magical Barrier Particle body; he wields a khakkhara and specializes in necromancy.