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

After working herself to death in the real world, Azusa Aizawa was reincarnated as an immortal witch in another world where she spent 300 years enjoying a peaceful life. However, she killed tons of slimes to pay her bills and gained experience, reaching level 99! Now, she has a solid reputation and attracts curious adventurers, dueling dragons, and even a monster who mistakes her for its mother! All of this doesn't suit her, as she still yearns to take it easy...