Masaki Jōgasaki, an eighth-year super senior and president of Kyoto University's film circle, maintains a fierce rivalry with fellow student Seitarō Higuchi, termed their "proxy-proxy war." This conflict traces back to their shared past as classmates with Ryōko Hanuki and a ramen stall owner. Despite his handsome appearance and popularity, Jōgasaki privately harbors lecherous tendencies, notably cherishing a love doll named Kaori with genuine affection and care.

He frequently acts antagonistically toward the protagonist, aided by Ozu in schemes actively undermining the protagonist's goals. This dynamic persists alongside Ozu's simultaneous claims of assisting the protagonist, weaving a complex web of alliances. Jōgasaki exerts manipulative influence within the film circle, designating Ozu as his successor in the proxy war against Higuchi.

In *The Tatami Time Machine Blues*, Jōgasaki displays unexpected caution when confronted with a time machine, questioning its reliability and the consequences of altering the past while others rush to use it. His subsequent tampering accidentally transports him 99 years into the past. Abandoning an air conditioner remote in a swamp during this incident inadvertently establishes him as the legendary "Kappa Lord" in local folklore. This event forms a stable time loop, as the remote remains buried for decades before resurfacing in the present.

Jōgasaki's protective relationship with Kaori surfaces when plans to steal her are thwarted by the protagonist. His rivalry with Higuchi occasionally erupts into physical confrontations, including an attempt to throttle the protagonist in one timeline, though such conflicts are typically tempered by other characters' interventions.