Edison format ruling
Archlord Zerato
Card text as printed in this era© Can't be Normal Summoned/Set.
© Must be Special Summoned by Tributing 1 face-up "Warrior of Zera" you control,
while "The Sanctuary in the Sky" is face-up on the field.
① You can discard 1 LIGHT to the GY; destroy all monsters your opponent controls
(Activate and resolve only if you control "The Sanctuary in the Sky").
Rulings
- The only way you can Special Summon this card is via its own procedure. Even if it was initially summoned that way, you still can't summon it with card effects.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Edison forum — sourced change requests get reviewed.