Shinkuro Isaka

Shinkuro Isaka (井坂 深紅郎), who was able to become the Weather Dopant (ウェザー・ドーパント) was one of the main antagonists in Kamen Rider W and the archenemesis of Kamen Rider Accel.

History
Dr. Shinkuro Isaka was the 42 year old head physician at the Isaka Medical Clinic (井坂内科医院). Ten years ago, finding no meaning in his life, he encountered Ryubee Sonozaki attacking a group of people as the Terror Dopant. This brings maddening joy to the doctor and he made a point to get the Terror Memory for himself, experimenting on himself with numerous Gaia Memories with various Living Connectors on his body before Shroud gave him the Weather Memory in the hope that he would be powerful enough to eliminate Ryubee. As the Weather Dopant, he was armed with the whip-like Weather Mine (ウェザーマイン) and control over the weather: intense sunlight, heavy rain, lightning, tornadoes, and freezing snow.

He originally tested these abilities in a series of freezing, electrocution and drowning murders which included Ryu Terui's family, to whom he was only known as the "man with the W Memory (Ｗ（ダブリュー）のメモリを持つ男)". Isaka does not use a Gaia Driver, as he feels he doesn't need the protection provided, as he was unaffected by their corruption due to him being already intensely psychotic, and the limits imposed on the power of Gaia Memories due to the Driver annoy him greatly. The Weather Dopant can also withstand Maximum Drives, as he has augmented the Weather Memory with other Gaia Memories' powers. This skill and his knowledge of Dopant physiology makes him an ally to the Museum, due to his experiments he burns a lot of calories and eats enough in one sitting for several people as a result. He modifies Wakana Sonozaki's Gaia Driver to maximize her potential as the ClayDoll Dopant under Saeko's request.

After his identity was discovered during his failed attempt to add the Invisible Memory to his arsenal in episode 27, Isaka takes refuge in the Sonozaki estate where he convinces Saeko to take out her father so she can control the Museum and he can get the Terror Memory. Though he originally sees Saeko as merely one of his pawns and research material, he admits to having developed feelings for her. During his attempt to absorb the Quetzalcoatlus Memory, the Weather Dopant was finally defeated by Kamen Rider Accel Trial's Machine Gun Spike Maximum Drive, shattering the Weather Memory. Shortly afterwards, Isaka's excessive use of Gaia Memories causes his body to become covered in Living Connectors that dissolve him away into nothingness as he tells the Kamen Riders that Shroud will be their end.

Shroud later expressed regret to Ryu for giving Isaka the Weather Memory, having no idea of what a monster he would become with the Memory.

Kamen Rider Battride Wars
The Weather Dopant appears as a boss in the video game Kamen Rider Battride Wars.

Dopant Form

 * Height: 248cm
 * Weight: 115kg

By using Weather Memory, Isaka is able to transform into the Weather Dopant (ウェザー・ドーパント). As Weather Dopant, he was armed with the whip-like Weather Mine (ウェザーマイン) and had control over the elements (which can augmented into the Weather Mine): intense sunlight, heavy rain, lightning, tornadoes, and freezing snow. He originally tested these abilities in a series of murders which include Ryu Terui's family, to whom he was only known as the man with the W Memory (Ｗ（ダブリュー）のメモリを持つ男). Isaka does not use a Gaia Driver, as he feels it only limits the power of Gaia Memories, and he is unaffected by their corruption as he was already intensely psychotic. The Weather Dopant can also withstand Maximum Drives, as he has augmented the Weather Memory with other Gaia Memories' powers. This skill and his knowledge of Dopant physiology makes him an invaluable ally to the Museum.