Poseidon

"Do not beg for your life, it is a waste of time."

Poseidon (ポセイドン) is a Greeed-like entity who posesses Michal Minato and becomes Kamen Rider Poseidon (仮面ライダーポセイドン, Kamen Raidā Poseidon), and is the movie-exclusive Rider who appeared in the OOO section of the Movie War Mega Max film.

Poseidon
Poseidon is a Greeed-like entity formed from the Cell Medals and Core Medals within Michal's body, turning him evil 40 years into the future. As Michal, he is given three Core Medals and the Poseidon Driver which he receives from the remnants of the Kougami Foundation in his time. He then becomes able to transform into Kamen Rider Poseidon. He then arrives to the present time in Michal's body to eliminate all Kamen Riders. The Kamen Rider Poseidon entity is eventually split from Michal's body in his Kamen Rider Poseidon form.

Kamen Rider Poseidon is defeated by Kamen Rider OOO Tajadol Combo's Prominence Drop and Kamen Rider Aqua's Oceanic Break, with his Core Medals taken for Kannagi to transform into the Super Galaxy King.

Kamen Rider Poseidon

 * Height: 204cm
 * Weight: 89kg
 * Punching Power: 3.5t
 * Kicking Power: 7t
 * Maximum Jump Height: 45m
 * Maximum Running Speed: 100m/6.1s

Similar to OOO, possessed Michal puts three Core Medals on the Poseidon Driver, and transform into the evil Kamen Rider Poseidon. The chest design have an inverse triangular position, which are arranged in the order of the Same on the right, Kujira on the left, and Ookamiuo below the Same and Kujira, unlike OOO's straight and diagonal arrangement. Kamen Rider Poseidon is designed as the light blue Same Head, the dark blue Kujira Arms with a whale's head on right shoulder and whale's tail on the left shoulder, and the dark red Ookamiuo's legs. Kamen Rider Poseidon uses a crimson spear as weapon.

Kamen Rider Poseidon, who is actually a Greeed, inside Michal's body. The Greeed overtook Michal's body and arrived to the present. It has the ability to create Waste Yummy, like how Uva did. The Greeed split from Michal, after losing some Core Medals to Eiji and Ankh. He was able to form his own body by using Core Medals and Cell Medals, in the form of Kamen Rider Poseidon. Then, Poseidon has been defeated at the hands of Kamen Rider OOO Tajadol Combo's Prominence Drop and Kamen Rider Aqua's Oceanic Break. However, Kamen Rider Poseidon's Core Medals are taken for Kannagi to tranform into the Super Galaxy King.

Poseidon Driver
Just like OOO, Poseidon Driver (ポセイドンドライバーPoseidon Doraibā ?) also utilizes Core Medals and is somewhat simpler-looking, shaped in a circle with outer design. Unlike the way OOO arranges his Core Medals to transform, Poseidon had his Core Medals put in an inverse triangular position on the Driver rather than being straight and diagonal, like OOO's. It does not require a scanner like OOO does.

Deepest Harpoon
Deepest Harpoon (ディーペストハープーン, Dīpesuto Hāpūn) is an large crimson harpoon which serves as Poseidon's primary weapon.

Core Medals
Just like OOO, Poseidon uses three marine life Core Medals (コアメダル, Koa Medaru). But unlike OOO's Core Medals, these three Core Medals that Poseidon have are created by Kougami Foundation by Kosei Kougami, as well as the fact that one of the Cores does not have the same color as the other two. These three Core Medals does not belong to any of the Greeeds, and it is only used to utilizes the Poseidon Driver to transform into Kamen Rider Poseidon.

Head:
 * Same Medal (サメメダル Same Medaru): The light blue Shark Medal, enabling Poseidon to use the Same Head.

Arms:
 * Kujira Medal (クジラメダル Kujira Medaru): The dark blue Whale Medal, enabling Poseidon to use Kujira Arms, it also gives Poseidon a whale shoulder design.

Legs:
 * Ookamiuo Medal (オオカミウオメダル Ōkamiuo Medaru): The dark red Wolffish Medal, enabling Poseidon to use Ookamiuo Legs.