Advanced format ruling
Gravekeeper's Chief
Card effect (current official text)You can only control 1 face-up "Gravekeeper's Chief". Your GY is unaffected by "Necrovalley". When this card is Tribute Summoned: You can target 1 "Gravekeeper's" monster in your GY; Special Summon that target.
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.