Goyō Yasui is the primary enforcer and personal bodyguard for Director Torauma, head of Torauma Industries. The Director specifically chose Yasui as his intended corporate heir, planning to cement this succession by arranging Yasui's marriage to his daughter, Yumi Torauma. Yumi, however, resists this plan due to her existing romantic relationship with Subaru Marita.

Acting as a formidable physical obstacle, Yasui works to eliminate Subaru as a rival and enforce the Director's plans. He physically confronts Subaru at Tokyo Airport, easily overpowering him and forcibly removing Yumi when the research team departs for Vietnam.

Following Director Torauma's death when the alien entity Zamba destroys his airplane over the Pacific Ocean, Yasui moves to seize control of Torauma Industries. He explicitly states his intent to marry Yumi to legitimize his claim over the empire. Pursuing Yumi into the snowbound mountains near Mount Washidaka after she flees, he catches her just as Zamba arrives. Yasui meets his end when Zamba attacks and kills him during this pursuit, eliminating him before he can reach Subaru, Yumi, and Lamina at their refuge.

Characterized as a sinister figure aligned with corporate power, Yasui consistently acts as an obstacle to the relationship between Subaru and Yumi while advancing the antagonistic goals of the Torauma faction.