Kimi no Tame ni Onee-chan ga Minna Koroshite ageru -Project Dia Horizon- 2 (Gangan Comics UP!)

[Machine Translation] The Otherworldly Death Game, Settled! Let me be your big sister for you. Reiji Kamiki, a university student, is reincarnated into another world by a fairy who suddenly appears and participates in an unreasonable death game that begins there. He and his mysterious "sister," Hilde, who is a reincarnated Reiji and who reminds him of his deceased younger brother, cooperate to defeat the participants of the game one after the other. They arrive at the church where the game began...? The blood-soaked bond between the two leads them to a horrifying conclusion to the Death Game!

異世界デスゲーム、決着！！　「君のためのお姉ちゃんでいさせて。」突如現れた妖精の手によって異世界に転生させられ、そこで始まった理不尽なデスゲームに参加することとなった大学生・神木怜二。転生した怜二の姿に亡き弟の面影を重ねる謎の『姉』・ヒルデとの協力で、ゲームの参加者を次々と打ち破っていく。二人がたどり着いた先にあったのは、ゲームの開始地点・教会で…？　「――私達の道を阻む子は、お姉ちゃんがみんな殺してあげる」血塗られた絆のその先に紡がれる、戦慄のデスゲームの結末とは！？