Dragon Quest Monsters: Joker Hints

After beating the game, u will have to attempt solitare's challenge, well after u beat the challenge and Solitare herself, you will be given a brass key. After u get it, go to the sewer and find a metal door. Use the brass key to open it and you will find another room, which happens to be Snap's reserch lab, and in the back is the Estark. If you beat it, it will join your team. It should be at lv30.

Complete the following tasks to get the monster... (You get the monsters from the helpers in Dr. Snapps office at the very end)

Empyrea: Get all monsters.
Grandpa Slime: Get 200 monsters.
Leopold: Get all skills.
Liquid Metal Slime: Get 100 monsters.
Metal Kaiser Slime: Get 150 skills.
Metal King Slime: Get 100 skills.
Robbin' Hood: Successfully complete the monster and skill libraries.

Get ten slimes keep combinins and leveling until it shows a king slime {this really works} or you can go to the uncharted island get two of the bemoth slimes and combine them