Reincarnated as a demon inside a dungeon

When people die, where do they end up to? I don't know about anyone else, but when I died, I arrived at the strangest Heaven of all times. And I got a chance to reincarnate with all of my memories! Jackpot! If you look away from the fact I had to reincarnate as a damn monster which is the lowest of all the bottom feeders? And I had to represent one of the worst goddesses ever!? And to make things worse, my “birthplace” was a freaking Dungeon! And not your everyday Dungeon with level 1 slimes and goblins, but a freaking Dungeon-turned-world-destroying-facility! Still, you gotta work with what you have. So see me how I survive in this crazy new world!! ...But I promise I won't be mad if the bosses get debuffed. No? Damn...