Kamen Rider Sting
Christopher Ramirez, nicknamed Chris, was originally supposed to be a Marine like his father, to uphold a family tradition (four generations of Ramirez men have been marines since WWII). Unfortunately, he was discharged for having asthmatic complications that would endanger his life as a soldier, leaving Chris and his father Sargeant Daniel Ramirez's relationship strained. While Chris' father and the doctor argued, he was approached by Xaviax in the form of Special Agent Simons who gave Chris an Advent Deck under the assumption that he is fighting evil aliens from another dimension and becomes Kamen Rider Sting armed with a stingray Advent Deck. Meanwhile, JTC shows Maya pictures of Chris in Kamen Rider form when he appears to her in person. In attempt to bring Chris into the open, Maya and her friends staged a monster attack with little success. Maya did, however catch Chris in action fighting a Mirror Monster. After destroying one of Xaviax's monsters alongside Dragon Knight, Chris proceeds to arrest Kit under the assumption that he is one of the aliens. They soon notice a fight between Kamen Rider Wing Knight and Kamen Rider Thrust. After Thrust leaves, Chris briefly fights Wing Knight as Kamen Rider Dragon Knight tries to convince him to fight him. Kamen Rider Sting later fights Kamen Rider Wing Knight and their battle continues in Ventara. But an asthma attack leaves Chris defenseless. Kamen Rider Wing Knight shows mercy and does not vent Kamen Rider Sting. This action sows the seeds of doubt in Chris's mind, and after further urging from Maya, Chris decides to team up with Len and Kit and fight against Xaviax and his evil plans. He helps Kit try to get Brad to help fight Xaviax, but unfortunately Brad refuses to listen. Following Kamen Rider Thrust being sent to the Advent Void, Chris is told about the Advent Void and agrees to help Len and Kit. Chris is brought up to speed when Kit, Len, and Maya tell him about Xaviax and what has happened up to now. After talking to them, he states that they must stop Xaviax at all costs. However, he refuses to help Kit and Len prompting Maya to go after him. When she does go after him, he recaps to her what he did before learning that Xaviax tricked him. After that, he is attacked by Kamen Rider Strike where he is then saved by Wing Knight and Dragon Knight. While meeting up with JTC, he confronts Strike once more putting up more of a fight thanks to a little training by Len. Strike leaves as soon as Wing Knight and Dragon Knight show up once again. JTC later attempts to change Chris's loyalties, saying that Xaviax would use high-tech medical technology to cure his asthma ("You can be a Marine again"), as long as he betrayed and vented Wing Knight. Chris doesn't listen, citing the Marine motto Semper Fidelis , or "Always Faithful". The two transform and fight once again, and Chris manages to escape on Evildiver. Chris continues to fight knowing full well his asthma would eventually overtake him and threaten his life, but he would rather go down with honor than stay on the sidelines. During a battle with Strike, Axe and Spear, Len is almost vented by Strike, but Chris jumps in the way, sacrificing himself to save his friend. Chris is the fifth Kamen Rider to be vented in the series, but the first one that was fighting for Earth and Ventara as opposed to their own interests.
During the final battle, Eubulon rescued the Ventaran Sting and used his Link Vent to destroy Xaviax. Eubulon later rescues Chris from the Advent Void and erased his memories as well as curing his asthma. During the Epilogue, he returns to the Marines to fight for his country once more.