Haru Tennōji is one of the two protagonists of the story and the co-founder of the startup company Trillion Game. He is a young man with an ambitious and unapologetically selfish nature, famously proclaiming his goal to earn one trillion dollars and obtain everything the world has to offer. Physically, he is depicted with brown hair worn in a ponytail and blue eyes, often dressed in a suit. His background reveals a pivotal moment in his youth: during middle school, he intervened to save a boy named Manabu Taira from being bullied. After witnessing Taira use his exceptional hacking skills to delete incriminating security footage, Haru recognized his talent and the two became friends. Years later, after Haru briefly worked for the giant IT corporation Dragon Bank, he quit when the company refused to hire Taira, whom he calls Gaku. He then convinced Gaku to abandon his job search and join him in building a business from the ground up.

Haru's personality is defined by a remarkable and multifaceted intelligence. He possesses superhuman communication skills and charisma, making him a natural seducer of people, which he leverages to charm investors, partners, and customers alike. His thinking is exceptionally fast, allowing him to devise complex schemes and adapt to rapidly changing circumstances in negotiations and business battles. Alongside this mental agility, he also demonstrates considerable physical strength. He is utterly pragmatic and views rules as obstacles to be circumvented if necessary; he lies with ease and will use any means, no matter how unscrupulous, to achieve victory for his ventures. Despite this ruthless ambition, Haru has a distinct code regarding loyalty. He places immense value on his partner Gaku's engineering abilities and consistently supports him. Furthermore, he reacts with swift and decisive wrath against anyone who harms or wrongs a person under his protection.

In the Trillion Game company, Haru serves as the public-facing leader, handling sales, negotiations, and strategic decision-making. His role contrasts sharply with Gaku, who is the introverted and technically brilliant developer behind the scenes. The relationship between Haru and Gaku is the core of the narrative. While Haru is the driving force and the one who constantly pushes forward, Gaku provides the sincere, technical foundation that makes their ambitions possible. Their partnership is one of complementary opposites, where they continuously influence and strengthen each other. Another significant relationship is with Kirika Kokuryū, the brilliant and arrogant heiress of Dragon Bank, who becomes both obsessed with their potential and a formidable rival. Haru consistently outmaneuvers her attempts at control, creating a tense and dynamic business rivalry. He also secures his company's first major investment from Kazuki Kedōin, a sharp-tongued venture capitalist who recognizes Haru's unique abilities.

Throughout the story, Haru's character shows a degree of development. While he remains largely the same confident and scheming mastermind, his actions highlight a distinct difference between his philosophy and that of the story's main antagonist, Dragon Bank president Kazuma Kokuryū. Where the antagonist seeks to devour and destroy all competitors, Haru's ambition is more about obtaining and building his own empire, though his methods are often morally ambiguous. A persistent mystery in the narrative is his absence from the present-day timeline. The story is told as a flashback by Gaku, who is the company president in the current day, and the reason for Haru's disappearance is a central, unresolved question. Among his notable abilities, in addition to his business acumen and physical prowess, Haru is multilingual, demonstrating fluency in English, Chinese, and French, which he uses to his advantage in international contexts.