Short description on story:
He was once hailed as the Sage Emperor, although not the strongest in the world, he was the most knowledgeable. People traveled great distances to seek him for help with their cultivation. One day he suddenly died in an ancient ruin and when he thought it was all over he was given a second chance. He reincarnated, not as a human but as a dungeon! Join our MC as he is thrown into a world of magic and fantasy!
P.S. This is not an OP MC story, the MC will be starting from the beginning. While he has the benefit of his previous knowledge there are large drawbacks as well. I want to clarify this as my description can lead to the assumption of an OP MC.
Link to story : http://royalroadl.com/fiction/7318