Megahex

Megahex (voiced by Shin-ichiro Miki) is the main antagonist of Kamen Rider × Kamen Rider Drive & Gaim: Movie War Full Throttle. Near the end of the second part of the movie, he absorbs Cyberoid ZZZ's body and becomes ZZZ Megahex (ZZZメガヘックス Surī Zeddo Megahekkusu).

Megahex was originally part of an unknown alien race which encountered the Helheim invasion. Being chosen to be the Man of the Beginning of his race, Megahex assimilated with its entire planet along with its inhabitants into a singular, mechanical being, with the planet itself becoming known as Planet Megahex (惑星メガヘックス Wakusei Megahekkusu).

Megahex appeared and attacks Planet of Helheim one day and attacks Kouta, as well as kidnapping Mai. During their fight on the planet, Megahex learns of the planet Earth from reading Kouta's memories and creates a portal to Zawame with Kouta transforming into Gaim Kiwami Arms to stop him. But Megahex succeeds in reaching the planet as Gaim destroys him with a a Burai Kick, only for the Kamen Rider to be defeated and destroyed by a second Megahex who takes the Kiwami Lockseed to incorporate into his systems. When Takatora Kureshima demands an explanation from Megahex, the being reveals his intend to assimilate Earth and begin assimilating a section of Zawame and any unfortunate humans caught in the process. When Mitsuzane Kureshima stands in the way, Megahex uses Kouta's memories to create Mecha Kurokages and then Mecha Ryoma Sengoku to drive Mitsuzane off.

The following day, as Takatora battles Mecha Ryoma, Mitsuzane stormed Megahex's ship as Ryugen, fighting through Mecha Roidmudes before saving Mai. As he did, Megahex appears behind Takatora as Kamen Rider Zangetsu, weary from his fight with Mecha Ryoma as Kamen Rider Duke Dragon Energy Arms, and smacks the White Armored Rider to the ground before incorporating the Kiwami Lockseed. Now boosted by the seed of the Golden Fruit, Megahex attacks Zangetsu with cold savagery, even using artificial Helheim vines spawned from his body until he knocked Takatora out of his transformation, landing near Mecha Ryoma's remains, chiefly near his Genesis Driver. Despite the beatdown, Takatora refused to give up, and when Megahex tries to cut Takatora down, Mitsuzane throws to Takatora the Melon Energy Lockseed. Thinking quickly, Takatora grabbed the Genesis Driver and lifts it up so the Melon Energy Lockseed inserts and locks itself into place, then slams it on, generating the Zangetsu Shin Genetic Ride Wear to protect Takatora.

With a passionate speech, Takatora completes the transformation into Kamen Rider Zangetsu Shin, battering Megahex back with Ryugen's support despite being outmatched. But Takatora pulls a risky gambit to remove the Kiwami Lockseed from Megahex's body, the entity furious of losing the item as he proceeds to obliterate the Kureshima brothers and Mai, but Kouta reconstitutes himself while deflecting the attack. The three Kamen Riders proceed to destroy Megahex, only to find more drones arriving as Megahex reveals that they have been fighting a few of a nigh-endless supply drone bodies which proceed to scatter to commence total assimilation of planet Earth.

One of the Megahex drones lands near Shinnosuke and Kiriko upon notcing the deactivated husk of Cyberoid ZZZ's body after it was abandoned by Zoruku Tojo's consciousness. Megahex assimilates the Cyberoid and transforms into ZZZ Megahex, flying back to Zawame to distribute the upgrade to Planet Megahex. Once arriving to Zawame, creating an army of Mecha Roidmudes and Mecha Inves with Kamen Rider Drive arriving after him, Megahex creates a replica of Kaito Kumon to deal with the interlopers. But the copy proved too much like the original to obey Megahex, forcing the entity to fight Gaim and Drive. Though they countered ZZZ Megahex, his ability to regenerate makes him a difficult opponent for the Kamen Riders until they receive their Type Fruits and Drive Arms forms to destroy him.

The ZZZ Megahex data is transmitted to Planet Megahex as consequence, with Megahex creating several ZZZ Megahex drones with some combining into the Z Mega Bat to hold off Drive and Gaim when they use Tridoron after a Shift Fruits Tire Expansion to reach the planet's location, somewhere in between the Asteroid Belt and Jupiter. As they arrived near the core, the Z Mega Bat stood in front of them shooting missiles, and the walls closed in to attempt to crush Tridoron, prompting Drive to eject him and Gaim out of Tridoron, allowing them to perform a decisive Double Rider Kick to slam into Z Mega Bat towards the ground, followed closely by Tridoron slamming into it, allowing them to slam into the core, permanently destroying Megahex with all his creations shutting down.