ELYSION virtual region (Kasou Ryouiki no Elysion, 仮想領域のエリュシオン) is a light novel series written by Kazuma Jouchi (一麻 上智) and illustrated by nauribon (なうりぼん).
Published by the MF Bunko, the series is complete at three volumes.
An incredibly athletic older brother, Tenryo Taiga. A programming genius girl, Tenryo Fuyuki. Siblings separated for 8 years ended up living under one roof again, after facing the problem – a lack of funds for living expenses. Fuyuki proposes a way to earn money, a core system deeply involved in people's daily lives, a game that awards you money as a prize for defeating malicious bugs in the cyber world, the 《Aries》 structure. Taiga relying on his inborn senses becomes a warrior in the game, and is puzzled by the unfamiliar sensation of the game world. One day Saionji Rui, Fuyuki's best friend appears and is attacked by a mysterious bug― “I'll be waiting, my prince.”. The hybrid fantasy battle of cheating siblings begins here!