Keyes is an Etherious and was a member of the now-disbanded Dark Guild Tartaros, and was a member of the Nine Demon Gates. Keyes is very silent and mysterious demon, rather saying a word, although he usually mutters. He has a calm and sadistic demeanor, even when he is about to face his enemies, as he eerily threatened Lucy, Wendy, Carla and Happy before confronting them.

Classification: Demon(Etherious), Tartaros Guild member, Nine Demon Gates

Powers and Abilities: Superhuman physical characteristics, extrasensory perception, curse manipulation, empowerment, limited absorption, immortality (Types 1 and 4), necromancy, intangibility, poison manipulation, power nullification

Attack Potency: Island level+(Fought and damaged Juvia)

Speed: Sub-Relativistic+(Kept up with Juvia)

Lifting Strength: Unknown (Not shown to be physically strong)

Striking Strength: Unknown(Not shown to be physically strong)

Durability: Unknown (Not shown to be physically strong). His Magical Barrier Particle body also makes him intangible and ignores physical and direct magical attacks

Stamina: Superhuman (Can fight for long periods of time despite sustaining severe injuries)

Range: Hundreds of meters

Standard Equipment: Khakkhara

Intelligence: Gifted(Can manipulate people and raise the dead)

Weakness: Weak to devil slayer magic. His type 4 immortality comes from the Hells Core Machine within the Cube, so if it's destroyed he loses his ability to revive. Can be killed if damage from the inside.

Notable Attacks and Techniques:

•Necromancer: Using his Curse, Keyes has the ability to perform necromancy, which allows him to revive and control a deceased person, as seen when he used Crawford Seam to remotely activate Face. Keyes is able to reanimate hundreds of corpses at a time, which allowed him to determine how much a corpse could behave like it's former self. However, corpses revived under Keyes control may only exist for a limited time unless they possesses a driving force, as Silver's desire for revenge against Demons allowed him to stay reanimated much longer than other corpses. Furthermore, if Keyes is defeated, corpses under his control will cease functioning.

•Magical Barrier Particles: Keyes body is made up of thick black particles, allowing him to move similar to a mist and cause both Magic deficiency and illness, as seen after Juvia forcibly exited his body. The said ability allows Keyes to deform and reform his body seemingly at will to avoid physical and magical attacks, though he has also been seen utilizing the ability almost unconsciously, being able to dodge a sneak attack by Gray with no effort at all by morphing his body as soon as the Ice-Make Mage made contact with it. Offensively, Keyes can manipulate the poisonous anti-Magic particles in various ways such as spiraling currents, a wave, or an explosion to attack opponents.