The Hydra Phantom has underwater capabilities, with which he can swim at a very fast rate, though Wizard in Water Style manages to outpace even him. He is also armed with many tentacles on his body, which can extend to a very long size as soon as the Hydra Phantom wants. For close combat, Hydra is armed with a spear.
His Gate target is Hiroshi Oikawa, an artist who he had spied on while underwater and was about to bring him into despair until Kamen Rider Beast fights him, only then for Kamen Rider Wizard to come and aid Kamen Rider Beast, who had refused his help. Shocked that there are two magicians, the Phantom escapes.
Later on, the Phantom targets Oikawa again until he fights Kamen Rider Wizard Water Dragon who he had overpowered and just as he was about to perform his finishing attack, Kamen Rider Beast Buffa Mantle intervenes and starts to attack Kamen Rider Wizard, and preventing him from fighting the Phantom and getting near Oikawa who was knocked out by the Phantom prior.
Under the assumption that Phantoms in the Underworld can give him a lot of mana thanks to Medusa, he lets the Phantom put Oikawa into despair and then he and Kamen Rider Wizard start to fight as the Phantom escapes again. As Rinko and Shunpei protect Oikawa from harm, Hydra destroys the portrait painting of his deceased wife by the aid of the Ghouls, plunging him into despair with time running short.
With Kamen Rider Beast entering Oikawa's Underworld to confronts his inner Phantom Bandersnatch, Kamen Rider Wizard fights Hydra alone, and manages to corner him in a forest clearing, and changes to Land Style to fight Hydra, but was overpowered. Koyomi soon arrived to give Haruto the new Rings, and transformed into Land Dragon form. After a few uses of the Gravity Ring, Wizard used the Special Ring to summon the Drago Hell Claws and rended Hydra into pieces with one swing of his new claws.
- Gate: Unnamed diver
- Episodes: 18-19
- Destroyed by: Kamen Rider Wizard Land Dragon's Dragon Ripper
- Mythological Basis: The Hydra
- Height: 230 cm
- Weight: 150 kg