Below are a list of some rare monsters in the game, and how you can acquire each one.

• Empyrea - Capture each monster
• Grandpa Slime - Capture any two-hundred monsters
• Leopold - Acquire each skill
• Liquid Metal Slime - Capture one-hundred monsters
• Metal Kaiser Slime - Acquire one-hundred fifty skills
• Metal King Slime - Acquire one-hundred skills
• Robbin Hood - Capture each monster and acquire each skill