|Full Name: Sosuke Esumi|
|Ranger Designation: Go-On Red|
|Weapons: MantanGun, Road Sabre, Handle Blaster, Go-Roader GT, Kankanbar|
|Gear: Go-Phone, Speedor Engine Soul, Change Soul, Blaster Soul|
|Engine: Speedor, Kishamoth, T-Line, K-Line|
|Sosuke is a optimistic former race car driver, who is always full of confidence. He is sure to confront obstacles the best he can. He has a habit of flipping of a coin (that has the Go-Onger logo on it) and for the majority of the time it ends up 'heads.' His nickname is the Speed King. When evil is present, he will not hesitate to fight right away. His prime attack as Go-On Red is Speed Rush. Sosuke and Speedor are very much alike and very good friends. Sometimes Speedor is more sensitive than Sosuke but all in all, Speedor is very loyal to Sosuke, but he is not above calling his partner out. He initially clashes with Gunpei, but they slowly become comrades. It was later when he came head to head with Hiroto, who doesn't completely take Sosuke seriously, only when it comes to defeating the enemy. It was until Episode 23 that Hiroto accepts Sosuke's reckless and random fighting style as he defeats Hiramechimedes. In Episode 8, the main three Engines were rusted and remained in their small Engine Cast forms and Sosuke was unable to clean the rust off Speedor. He kept expecting a miracle to occur. Fuji, his former team supervisor, had been observing him and clarified to him that he didn't win races on his own, that the mechanics prepared for his reckless driving. So, with realizing that a hero is not alone and that wanting for miracles won't help anything, Sosuke put some elbow grease into it and cleaned Speedor in time to help their friends.
Sosuke is protective of Saki and Hanto, probably beause they are the youngest of the team. When Saki started hanging out with a flutist by name of Seji in Episode 6, he believe she wanted to marry him and he became overprotective and maybe even jealous. In Episode 12, he switched bodies with Hatsuden Banki and to return him to his body, the Engines made him into a Engine Soul to re-enter his body, ejecting Hatsuden out. In Episode 33, because of Sosuke's passion to continue fighting is why the Anicent Engines agree to help the humans against the Gaiark. At the end of Episode 35, Yogostein injects a gear inside of Sosuke that rusts his entire body, causing him to die slowly. Because of his friends' belief in him and their perseverance, restores him. The Ancient Engines then blame themselves for Sosuke turning to rest because they let themselves be turned evil when Yogostein injected in Sosuke. Hiroto convinces them and get them over it.
By the finale, Sosuke took it very personally when Yogoshimacritein conducted the Justice Dissolution on Gunpei and Hanto and he did not want to listen to rhyme and reason. Hiroto deliver him a speech that because of him, he realized they are in it together. When Hiroto and Miu were made victims of Yogoshimacritein's, Sosuke claimed to forget the four fallen comrades but it was later revealed in battle that he had no forgotten his friends and fought Yogoshimacritein with the two Rocket Boosters. Several months after the finale battle, Sosuke's dream of going back to the track was proven to be much harder than he once predicted. He was so behind that he had to start from the very bottom... at the go-kart track. When his old temammates discovered this, Speedor and Bomper returned to recruit them to fight in Gunman World, which Sosuke gladly agreed to.
"Mach Full Force!! Go-on Red"