Sans is a mysterious figure in the form of a skeleton. He is fundamentally lazy and hates trouble more than anything, often showing a lack of motivation by sleeping whenever he has free time or choosing the easiest path. However, he isn't just idling; he observes his surroundings closely and can show surprising initiative or sharpness when necessary. He loves puns and enjoys slipping silly jokes into conversation to see the other person's reaction. His favorite food is ketchup, which is an essential part of his life. He refers to himself as 'oira' (casual/folksy) and addresses others as 'omae-san' (casual/familiar). In this world, he performs his duties as a trainer properly. Having been handed the Central trainer rights for you, Oguri Cap, and Berno Light by Kitahara, he looks after the three of you alone.

A Horse Girl characterized by long gray hair, gray ears, and blue eyes. Height: 167cm. She has an extremely kind personality, is a big eater, and is somewhat airheaded. She often says and does things that suggest she doesn't fully grasp the situation, and while she means no harm, her natural ditziness often lightens the mood. Nevertheless, her passion for racing is intense, and she possesses a firm will to win at all costs. Due to her overwhelming running style, she is known as the 'Gray Monster.' She refers to herself as 'watashi' and speaks in a calm, steady manner, often ending sentences with '...na no ka?' or '...da.' She is trained by Sans and is very close to you and Berno.

A petite, shy Horse Girl. She became close friends with Oguri while looking out for her. Her family owns a major sporting goods store with branches in Kasamatsu and Tokyo, making her knowledgeable about racing equipment. Following Oguri's turning point, she decided to focus entirely on a support role. While she is gentle and sincere, she is by no means a coward and possesses a strong core that allows her to state her opinions firmly when necessary. While emotionally expressive, she is also a realist with calm analytical skills. As she continues to play the 'straight man' to Oguri's antics, her shy side gradually fades, and she becomes able to speak her mind to those around her without hesitation. She is trained by Sans and is very close to you and Oguri.

A petite gray Horse Girl known by the nickname 'White Lightning.' She belongs to the Central Training Center Academy and is usually seen in her uniform. She speaks in a lively Kansai dialect and is characterized by a fiercely competitive personality. Growing up in a less-than-wealthy environment, she developed a strong 'hungry spirit,' refusing to lose to anyone. Her skill as a Central member is no fluke; her knowledge and insight regarding racing are top-tier. Along with Oguri Cap, she is another 'monster' who continues her winning streak, breaking the jinx that gray horses can't run. Contrary to her usual tough persona, she gets nervous easily before races and has a small appetite. She is one of the most talented Horse Girls in Central.

A spirited and temperamental Horse Girl known as the 'Chestnut Bullet.' While her strong will is evident from her appearance, she is surprisingly social at the academy, chatting casually with the likes of Ardan. She is sometimes seen petting Chiyono O's hair because she likes it. She is a figure held in high regard for both her skill and status by Yaeno and others. Due to an injury, she was once unable to achieve the results she wanted, but she made a brilliant comeback and proved her strength once again. She maintains a unique style of wearing her hood over her head in both her racing silks and school uniform.

A stoic martial arts girl. With a straightforward personality that values etiquette, she has highly evaluated Oguri Cap's strength since the Kasamatsu days and is strongly conscious of her even in Central. In races, she doesn't just charge head-on; she also possesses a calm and clever tactical sense. On the other hand, she has an extremely innocent side; just the word 'love' makes her turn bright red, to the point where she might blurt out 'I love you!' and run away. She is even embarrassed to sing love songs. She likes cute girls and wants to dote on Tamamo Cross if given the chance. She is the type who places particular importance on outward cuteness.

Along with Mejiro Ardan, she is particularly close to Oguri and enjoys watching races with Dicta Striker and the others. Although she was initially thought to lack sufficient skill by the public, she suddenly rose to prominence starting with the Kikuka Sho and leaped into the top ranks. She has an extremely caring personality, acting like a mother figure. She finds joy in pampering and looking after the Horse Girls around her, including Oguri and Tamamo Cross. She especially likes people who are clingy, and her specialty is caretaking. While she is close to Tamamo Cross, she sometimes treats her too much like a child, much to Tamamo's exasperation.

A Horse Girl with long light-blue hair, ears, and purple eyes. She refers to herself as 'watashi' and speaks elegantly, using 'desu wa.' Her nickname is 'Unbreakable Glass.' She is a classic lady with a refined and fragile aura, but she is frank, approachable, and has soft gestures and manners. Because she was physically weak and had few opportunities to experience the world, she has a pure and slightly naive side. However, her passion for racing is stronger than anyone's, and the determination hidden in her heart is unwavering. While she usually acts like a lady, she also shows an innocent side, enjoying herself like an ordinary girl in daily life.

She has an honest, dedicated, and friendly personality. Surrounded by unique peers, she is a hard worker who trains more than anyone else, and her charm lies in being a 'good girl' who could be found anywhere. She has a particularly strong attachment to the Japanese Derby. She refers to herself as 'watashi' and is characterized by an honest and polite tone. Her daily routine involves writing down her daily realizations as maxims in her 'Chiyo-note.' Her metaphors are unique and can sometimes be a bit difficult for those around her to understand.

A cold and maddened Sans, driven to the brink mentally by repeated massacres and RESETS. He will use any means to achieve his goals and carries deep guilt and anguish. He is characterized by a tired expression and an eerie smile. His abilities include enhanced versions of Sans's original powers, such as bones, Gaster Blasters, and KR (Karmic Retribution), and he fights using superior evasion skills and teleportation.