Oz Academy
Following the folding of Gaea Japan, Nagashima affiliated herself with Mayumi Ozaki's Oz Academy promotion, which she now had turned into a full promotion. During 2005, Nagashima also made several appearances for the Hustle promotion, working under a mask as "Blanca X". In early 2006, Nagashima, along with several other Oz Academy workers, made her first trip to Mexico, taking part in events held by AAA. Back in Oz Academy, as representatives of the Oz Seikigun, Nagashima and fellow Gaea Japan alum Sonoko Kato became three-time Oz Academy Tag Team Champions. In early 2008, Nagashima returned to Mexico's AAA, taking part in the Reina de Reinas Universal Tournament, from which she was eliminated by Mari Apache. On September 23, 2011, Nagashima turned on the Oz Seikigun (正規軍) and joined the villainous Seikigun (正危軍), another incarnation of the original Oz Academy stable, after the stable's leader Mayumi Ozaki had announced that she was only going to be defending the Oz Academy Openweight Championship against her stablemates. On February 26, 2012, Nagashima defeated Seikigun stablemates Hiroyo Matsumoto, Ran Yu-Yu and Yumi Ohka to become the number one contender to the Oz Academy Openweight Championship. On March 25, Nagashima defeated Ozaki in a Dress Up Wild Fight 30 minute Time of the Trial match to become the new Oz Academy Openweight Championship. Initially a reluctant member of Seikigun, Nagashima embraced her "dark side" only after cheating to successfully defend the Oz Academy Openweight Championship against Hiroyo Matsumoto on August 19. Nagashima made her second successful title defense on January 13, 2013, against Seikigun's newest member, Mio Shirai. On April 24, Nagashima lost the Oz Academy Openweight Championship to Akino in her third defense, ending her reign at 395 days, the longest in the title's history. Afterwards, Nagashima came to odds with her Seikigun stablemates, which led to a Hair vs. Hair match on September 15, where Maymi Ozaki, waging both her own and the stable's manager Mika Nishio's hairs, defeated Nagashima, forcing her to have her head shaved. Nagashima finally turned on Ozaki and the Seikigun on January 12, 2014. On February 9, Nagashima suffered a cruciate ligament rupture in her left knee, forcing her to undergo surgery on February 18.