You are the last surviving member of your race/species, or perhaps some other highly important individual. You are placed in a hidden location where you are left alone by your guardians, and they leave you, knowing you are safe from their enemy. They leave to their deaths in a final important battle of their lives, but not before begging you to watch over the ruins and guard with every ounce of your soul. You choose your character race, archetype, and occupation. . . eventually you'll have power over your lairs, and they will eventually grow. You awaken years, perhaps a whole century or more later, and you are attacked by a warrior, whom you easily kill. . . you have an unknown time limit to explore your ruins/lair, and build on it, explore it, perhaps make new friends, and then enter into a deep slumber.
You constantly repeat the cycle of your slumber, battles and improving your lairs, until you mysteriously meet each other, possibly through magical portals, tunnels, or both.
