After reflecting on my death from overwork in the original world, I became an immortal witch with the help of the goddess and lived leisurely for 300 years—only to find out that I had reached level 99 = the strongest in the world. Could it be that the experience points I accumulated from catching slimes in my spare time piled up too much? Rumors spread quickly, attracting curious adventurers, dragons challenging me to duels, and even a daughter who calls me "Mom"— Welcome to a unique isekai story of the strongest and slow life, where I only catch slimes! Come to my heartwarming home in the highlands!