"I Will Become Twintailed"), abbreviated OreTwi (俺ツイ), is a Japanese light novel series written by Yume Mizusawa and illustrated by Ayumu Kasuga.

With the armor, Soji transforms into a girl and twintail warrior (ツインテイルズ関係者, tsuinteiruzu kankei-sha) branded Tail Red, to protect Earth.

Although they are the villains of the story, the majority of them are rather silly and comical and behave much like otakus, often admiring cute girls, collecting dolls, and even adoring the twintail heroines.

Members include: Ore, Twintail ni Narimasu began as a light novel series written by Yume Mizusawa, with illustrations by Ayumu Kasuga.

A manga adaptation titled Ore, Twintail ni Narimasu π (俺、ツインテールになります。π) by Ryōta Suzuki was serialized in Square Enix's Monthly Big Gangan magazine, and was compiled into two tankōbon volumes.

[25] An anime television series adaptation, produced by Production IMS and directed by Hiroyuki Kanbe [ja], aired in Japan from October 9, 2014, to December 25, 2014.