Advanced format ruling
Gaap the Divine Soldier
Card effect (current official text)All monsters are changed to Attack Position, also their battle positions cannot be changed. (Flip Effects are not activated.) Once per turn: You can reveal any number of Fiend monsters in your hand; this card gains 300 ATK for each, until the end of this turn.
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.