Zombie Blood

Four roommates accidentally enter a barrier. With a mage's guidance, they discover an ancient tomb within, but they do not know what is imprisoned. Only by uncovering the cause and effect behind the barrier's creation can they close it. However, after solving the mystery, they unintentionally release the trapped entity—an ancient, indestructible zombie. Ultimately, joining forces with the mage, they manage to destroy only its evil intent. They think they can escape the barrier and return to normal, but instead are drawn into an even deeper vortex. — Description from novelcodex.org