Kotaro escaped before getting brainwashed (which is the final step in the surgery), with help from his foster father, and turned against Gorgom.

He soon finds out the horrific truth from his stepfather: Gorgom originally killed his true parents and, since both Kotaro and Nobuhiko were born on the day of a solar eclipse, are referred to as "Black Sun" and "Shadow Moon".

Kotaro, taking on the name of Kamen Rider Black, was determined to rescue his stepbrother from Gorgom while protecting Japan.

However, later in the series, Nobuhiko emerged as Shadow Moon to fight Kotaro with the survivor becoming the next Creation King.

The show's staff was confirmed in October 2021, with Izumi Takahashi as a screenwriter, Shinji Higuchi as a concept designer, and Kiyotaka Taguchi as special effects director.