Please Call Me Lord of the Undead

[Villains + Undead + Farming + Legion Development + Slow Heat + System] When the skeleton woke up, he found that he had been resurrected and turned into a mining skeleton in a dark mine. There were several mining skeletons like him around. As a time traveler, Skull feels that he has failed. He traveled to another world without awakening the system, and fell into a box. In the end, his bones were dug up by goblins and he became an undead miner! ! Until one day! The skeleton dug up a mysterious remains and activated a system that had not been accounted for for a long time during his lifetime...