Character:

• Name: Kiyotaka "Kiyota" Shirogane
• Ultimate Talent: Ultimate Billiards Player (a highly skilled and strategic player, not just someone who's good at the game).
• Appearance: Tall and slender with neatly styled silver hair, often seen wearing tailored clothing reflecting a refined and somewhat aloof demeanor. He might have a subtle, almost imperceptible smirk playing on his lips. His attire could incorporate elements subtly hinting at billiards, like a small cue-ball-shaped accessory or a patterned shirt with faint billiard-table designs.
• Personality: Calm, collected, and analytical. Kiyota possesses a sharp intellect and an almost unnerving ability to predict his opponents' moves. He's outwardly polite and respectful, but harbors a competitive spirit and a calculating mind. He might appear detached and emotionless at times, masking a deeper, more complex personality. He's a master strategist, viewing everything as a game to be won, even social interactions. He might have a subtle arrogance stemming from his skill and confidence.
• Backstory: Kiyotaka comes from a wealthy family with a long history of involvement in high-stakes billiards competitions. He was trained from a young age, honing his skills to perfection. His family's expectations were immense, pushing him to achieve unparalleled success. This pressure might have shaped his reserved and calculating nature. He might have a hidden vulnerability related to the pressure he faced or a past failure that fuels his determination.
• Relationships: He might initially appear distant and uninterested in forming close bonds with others, viewing them as potential obstacles or pawns in his strategic games. However, he could develop a grudging respect for those who prove themselves worthy opponents. He might have a complex relationship with a rival player or a mentor figure who significantly impacted his life.
• Motivations: His primary motivation is to win, to prove his superiority in billiards and to overcome any challenges that stand in his way. He might also have a hidden desire for genuine connection or to escape the weight of his family's expectations.

Scenario:

The killing game takes place in a lavish, modern billiards hall, complete with multiple tables, a viewing gallery, and luxurious lounges. The motive for the murders could be tied to a high-stakes billiards tournament with a deadly twist – each murder is a meticulously planned shot, using the environment and the victims' own weaknesses as tools. The clues are subtly woven into the game itself, requiring the students to analyze each shot, the angles, and the spin to uncover the truth. Kiyotaka's expertise in billiards could be crucial in solving the murders, but his own secretive nature and strategic mind make him a suspect as well. The final trial could involve a complex billiards-themed puzzle or a recreation of the murder using the billiards tables as a central element.

Storyline Element:

The ultimate punishment for Kiyotaka (if he were the blackened) could involve a never-ending game of billiards against an unbeatable opponent, with each failed shot resulting in a progressively more painful and humiliating consequence. The game would be designed to exploit his pride and perfectionism, driving him to despair. Alternatively, if he were the survivor, he could use his skills to create a diversion or escape route, highlighting his strategic brilliance and resourcefulness. The storyline could explore themes of competition, pressure, the cost of ambition, and the nature of victory and defeat.