Advanced format ruling
Goblin King
Card effect (current official text)While you control another Fiend-Type monster, this card cannot be attacked. The ATK and DEF of this card are each equal to the number of Fiend-Type monsters on the field (excluding this card) x 1000.
Current rulings for this card are maintained by Konami.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Advanced forum — sourced change requests get reviewed.