Gonna Be The Twin-Tail!! Vol. 5 (Light Novel)

In Vol. 5, summer arrives and the Twintails decide to hold a training camp. The destination? Another world! But on the way there, trouble strikes and they are forced to land on an unknown world. There, Soji meets a local twintailed warrior fighting a lonely battle. Meanwhile, Dark Grasper is given orders to eliminate the traitor Elemarian and sets off in pursuit. What is the true identity of the traitor? An unprecedented battle begins!
Notice: This book is written in Japanese.