Taiyō is Megumi's childhood friend, their bond rooted in a shared history within a grape orchard setting. After a period of separation, their reunion forms a core narrative pillar. Central to one storyline is the mysterious disappearance of Taiyō's "Sapphire Roman" grape seedling, prized for its potential to produce grapes of exceptional taste, propelling the plot. Their interactions consistently explore themes of reunion and their shared past. Available sources focus on this role and the described events, without providing specific details on Taiyō's personal characteristics, further development, additional background story, personality traits, or evolution in other official media beyond the documented commercial narratives.