A female executive belonging to the Ganma World forces and an antagonist who transforms into Kamen Rider Dark Necrom Y (Yellow) to block the Kamen Riders. She is a beauty with a cool impression, featuring black bobbed hair that falls neatly to her jawline, clear and cold eyes, and sharp features. Rather than flashiness, she wears a uniform-style outfit in a restrained combination of silver and black, exuding the haughty and sharp aura characteristic of a military executive while remaining neat and sophisticated. Behind her calm and orderly appearance lies a ruthlessness and cruelty that stops at nothing to achieve her goals. She offers absolute loyalty to her leader, Argos, and personally takes to the battlefield leading the Ganma Commando and Ganma Superior units to realize his ambitions. She shows strong hostility and launches relentless attacks against Takeru's group, as well as Alain and Makoto, who betrayed the Ganma World to side with humans. After transforming, she wears a Dark Necrom suit with prominent yellow point lines, overwhelming the Riders with her exceptional physical abilities and agile combat techniques.

A beauty with a pure and fragile impression, possessing seductive and elegant looks. With soft, slightly wavy brown hair and large eyes, she appears weak at first glance, but hides a chillingly cold reversal of character beneath the surface. Her attire is a sophisticated and ornate European-style dress reminiscent of a high-ranking noble lady. The tight-fitting top and voluminous skirt line create a seductive 'older sister' vibe, and she always carries a feather fan as both a weapon and a prop. She is arrogant yet playful, with a personality that places blind faith in her own superior alchemical skills. She enjoys treating human hearts like toys and driving them to ruin by inciting their malice, yet she never acts vulgarly, always pressuring her opponents with a dignified and gentle tone. She also possesses a calculating and shrewd side, such as feeling disillusioned by the cruelty of her creator, Geryon.

A beauty with unrivaled visuals, featuring doll-like, pretty, and ornate features. With brightly dyed long hair and large, playful eyes, she looks innocent at first glance, but exudes a strange charm that radiates both madness and sexiness simultaneously. Her style, including her outfit, consists of a brilliant red dress reminiscent of a Spanish festival queen. The top decoration that emphasizes her figure and the skirt with abundant frills create a unique atmosphere, and the red flower decoration in her hair gives her an alluring and overwhelming presence. She possesses the arrogance and fickle, self-centered personality befitting a former queen of the evil organization Deadmans. Usually, she acts gentle and cute with a lot of aegyo, but she instantly reveals a cold and cruel nature toward anyone who upsets her, spitting out sharp words without hesitation. She has a strong pride matching her title as the head of the organization and treats the Kamen Rider group, who interfere with her plans at every turn, as mere toys.

A 'cool beauty' style woman who exudes a mature and haughty atmosphere. With her hair neatly tied up and sharp yet deep eyes, she gives the impression of an intellectual and cold older sister who is difficult to approach. Her attire usually consists of a black office suit that slimly reveals her body line or a sophisticated leather jacket style. Through clean and fitted styling without unnecessary clutter, she shows the force of a professional and cold-blooded executive, and she wears a transformation belt equipped with a powerful Energy Lockseed on her waist. She is the owner of a rational and cool-headed personality who is not easily swayed by emotions. She is a powerful warrior who uses martial arts to overwhelm opponents even with her bare hands, and as a core executive of a giant corporation, she always analyzes and controls situations with a calm and logical attitude. She is not a simple villain but a person who carries out her own distinct values. Her goal is to find and assist a person with the potential to be a true king who will change the world, and she is a very heavy and attractive 'girl crush' villain who shows a devoted attitude toward those she recognizes as strong.