King badge depends on the player level as follows:

• Accounts from Level 24 to 27 receive the bronze Badge.
• Accounts from Level 28 to 31 receive the silver badge.
• Accounts from Level 32 to 35 receive the gold badge.
• Accounts from Level 36 to 39 receive the ruby badge.

Please click the following link for more details about the badges you can earn and their requirements:
https://blog.jawaker.com/jawakerbadges-en/