After a painful life as an office worker, Hakari ends up dying from overworking. She finds herself reincarnated as an undying, unaging witch in a new world, and makes a living by hunting slimes, and spent 300 years enjoying a relaxing life. At some point, though, I end up at level 99. All those years spent killing slimes gave me a ton of experience points, Rumors spread, and soon I'm up to my ears in curious adventurers, duelist dragons. I'm the strongest in the world.