Ohie Tachi is a third-year student at Jinkou High School and a member of the school's rugby club, where he plays as a prop. His full name is also presented as Taichi Ohie, with Ohie as the family name. He has a stocky build and is somewhat shorter than average for a prop, standing about 1.71 meters and weighing around 85 kilograms. He has short, curly dark hair and down-turned eyes that give him a soft, gentle appearance.

In terms of personality, Ohie is calm, easygoing, and kind, with a demeanor that makes him approachable. He is consistently helpful toward those around him, yet he also shows a subtle manipulative side; he is skilled at influencing the younger club members and occasionally stirring things up among them, though never for any serious or harmful purpose. Beneath his relaxed exterior, he is actually very intelligent, and he uses that intelligence to manage his juniors and keep the team dynamic running smoothly without creating discord.

His role in the story is that of a dependable senior member of the rugby club who provides stability and quiet leadership. As a prop, he is part of the team's forward pack, and he alternates with the teammate Shinshi Yutaka as a starter in matches. His key relationship is therefore with Shinshi, with whom he shares the starting role, as well as with the younger players, whom he handles with a blend of warmth and subtle guidance. His main motivation is to support the team through his experience as an upperclassman, using his social awareness to maintain harmony and his rugby skill to contribute on the field. His notable abilities include his sharp intellect, his capacity to handle interpersonal situations without friction, and his physical play as a prop in matches. While his development is modest compared to the lead characters, he serves as a steadying presence whose cleverness and easygoing nature help hold the club together.