Pharos Hercules

The main antagonist, a dream demon who leads a group of others to the real world so they can possess humans. His plan is to turn the real world into a place where dream demons can manifest without needing humans as vessels.

Appearance
Heracles looks like an armor, his skin is black with deck circle-shaped marks all over his body.

Personality
He is completely amoral, as he told Clione that he doesn't care about what happened to Ransborough or Chain Noir despite them being completely loyal subjects of his.

History
John stated that he and Merry arrived in the real world at around the same time, almost a decade ago, but that his power hadn't started manifesting until very recently.

At some point, he possessed Takateru Akiyanagi. He also forced Clione to possess Taka's younger sister so Clione could track down dream demons in the real world, furthering his cause.

Some of his minions included Ransborough and Chain Noir, though Merry successfully sent both back to the dream world.

Heracles has come to the human world to attract the other nightmares. To then make them fight and use their powers to harm both sides of the door for all the nightmares are forced to manifest in the real world without a vessel.

Powers & Abilities
He wields a scythe-like axe in battle, as when he fought Engi.

As of chapter 54, it seems that Hercules has the ability, like Yumeji, to use the Lucid Gadgets of other dream demons. He does so first by summoning Patty's sword to mock Enji, and later in battle when he summons Cactus's spikes to attack the group at once.

He can also summon his own Garden at will in place of other dream demons, and seems to favor using his insignia (his pupils) whenever using his powers.

He still needs a vessel to manifest in the real world as he uses Takateru Akiyanagi to pull everyone into his Garden.

Relationships
Takateru Akiyanagi: his human vessel. He has possessed Taka since the entire group was in elementary school, asking Yumeji not to look at his dream aura to avoid Yumeji discovering the truth of Taka's possession.

Sonar Clione: he forced her to possess Miyuki, Taka's sister, to locate dream demons in the real world.

Ransborough: along with Chain Noir, he commands them into recruiting more dream demons to possess humans in the real world.

Yumeji Fujiwara: he calls Yumeji his elder brother, although it's still unclear as to whether he meant it literally or something else.

Trivia

 * It was revealed that Takateru Akiyanagi is his vessel.