Ore, Twintail ni Narimasu.  

Gonna Be the Twin-Tail!!, Ore, Twintails ni Narimasu., oretsui, oretwi, Я буду хвостики носить, 저, 트윈 테일이 됩니다, 俺, ツインテールになります.

Twintails: The Treasure of Mankind-or at least that's what first-year high school student Souji Mitsuka believes. At school, Souji spends most of his time daydreaming about and rating girls with twintails, even going so far as to create a club dedicated to the hairstyle. His obsession is noticed, but when monsters from outer space attack Earth and claim the worlds twintails for themselves, a strange woman named Twoearle enlists Souji to fight back using his own twin-tailed powers! By transforming into Tail Red, Souji battles against Ultimegil, an alien organization determined to colonize Earth and steal everyone's spiritual energy or "attribute power." Along with fellow twin-tailed warriors Aika Tsube and Erina Shindou, Souji must find a way to defeat the invading army and protect his beloved twintails.

Ore, Twintail ni Narimasu. adapts the first 4 novels of Yume Mizusawas light novel series of the same title.