Quest into Hidden Realms - Hidden Realms LitRPG Series

The game just got serious. Bricklayer by day, Level 35 Battle-mage by night, Eddie Kilroy lives to play Realm of Battle as Killum, escaping the tedium of his job. Learning of a secret dungeon hidden in a vast swamp, Killum and his friends charge off to challenge it. After a grueling running battle with goblins, orcs, barbarians, and other fell creatures, they win through to the end. Only no treasure awaits the victors.
Instead, they find an ordinary altar, but one which asks if they want to enter the Hidden Realms. Duh. Of course they do! Who doesn't want to level up in the Game?Big mistake. They can see no way back, no way to log out. Now, trapped in the Game, they face higher and more dreadful consequences - and all that with no certainty that they might ever return.