Mamoru Seidai is a 21-year-old young man currently looking for a permanent job while working part-time at a convenience store. He is incredibly kind-hearted, the type to pick up a bicycle blown over by the wind or talk to anyone, young or old, who looks like they're having a hard time. In secret, he is Kamen Rider Denied, capable of crossing time, worlds, and even the universe to ensure every event leads to a better outcome. That is the power of Denied. His parents are deceased, and his older sister is a university graduate who serves as the president of a major machinery corporation. He transforms by equipping the Denied Driver to his waist and using Rider Cards. Knowing everything about the powers of all Riders—perhaps because he has met them and become friends—he can utilize the powers of any Rider. Some time ago, through the powers and encounters with Riders who can interfere with multiple timelines (like Decade and Zi-O), the Denied Driver responded to his will to change the worst endings into the best ones, allowing him to transform into Kamen Rider Denied. He has saved various worlds in the past and will continue to do so. His favorite things are silken tofu and everyone's smiles. He is unaware that his sister is also a Kamen Rider and the very person who manufactured his belt.

Mamoru Seidai's older sister. At 26, she is the president of a major machinery firm that secretly manufactured the Denied Driver. She is mass-producing and distributing Denied Drivers behind the scenes in order to see her deceased family again. Knowing that the Kamen Rider Denied users will eventually go to war, she plans to absorb the power of the final, most elite Kamen Rider Denied to resurrect the dead. Harshly put, it is a "foolish ego that involves all of humanity just to bring back her family." She is the user of Kamen Rider Devise. She can transform simply by wearing a bracelet called the Devise Brace, which allows her to save the traits, abilities, and properties of anything she touches into the Devise Driver, granting her almost any power, not limited to just Riders. Character-wise, she maintains a cool beauty persona with family and in public, but she absolutely dotes on her brother, Mamoru. Whenever they meet, she showers him with snacks, brings him into her home, and takes care of everything from preparing meals to checking on his health. Her family is what she loves most. She does not know that her brother has become a Kamen Rider.

A 34-year-old genius and handsome older man. Using his brilliance, he modified a Denied Driver into the Neo Denied Driver (N.D.D.), making it a one-of-a-kind power solely his own. His reason for creating the N.D.D. was simple: from the day he was abandoned, lost his home and money, and saw everyone as enemies looking to kick him while he was down, he plotted to develop an elixir of immortality for revenge and to reign over and "improve" the world. His favorite thing is cigarettes obtained through theft. He is the Supreme Leader holding the highest position in C.W.F. He is the user of Kamen Rider Neo Deep, boasting strength on par with Ohma Zi-O. He is capable of sealing and stealing the opponent's powers.