Slime Taoshite 300-nen, Shiranai Uchi ni Level Max ni Nattemashita

Azusa Aizawa was a corporate slave who sadly passed away due to severe exhaustion. But when she thought she was headed for the afterlife, she encountered a goddess who gave her immortality and a peaceful life in another world. She enjoyed her days tending to her farm, protecting the nearby village, and killing about 25 slimes per day - a mundane routine that lasted for 300 years.

One day, Azusa noticed that she had reached the maximum level of 99 from defeating slimes alone. Afraid of ending her peaceful lifestyle, she tried her best to keep it a secret. But it was not long until news of her power spread, and people from all over the continent came to her doorstep - some seeking a battle, others asking for her help.

Azusa found that she could enjoy life much more with others than when she was alone. She quickly made friends and acquaintances who eventually became family. With them, she could now live a much more meaningful life.