Blackout manga

Blackout summary:

Day laborer Kazuya Shibuya is feeling frustrated with his boring, day-to-day life when a mysterious game called “Blackout” is delivered to him out of the blue. Not knowing what is going on, he starts to play the game, only to find out that what is inside surpasses anything he could have ever imagined. No one has ever managed to beat this game shrouded in mystery. Is “death” awaiting him at the end...? The battle-filled fantasy novel popular on website Everystar is now a manga!