Edison format ruling
Hero Mask
Card effect (current official text)Target 1 face-up monster you control; send 1 "Elemental HERO" monster from your Deck to the Graveyard, and if you do, that target's name becomes the sent monster's name, until the End Phase.
Rulings
- Send 1 Elemental Hero monster from your Deck to the GY when you resolve Hero Mask.
- Hero Mask targets 1 face-up monster you control.
- If you select Grandmaster of the Six Samurai and change its name with Hero Mask's effect, and afterwards you Summon another Grandmaster of the Six Samurai, when Hero Mask's effect disappears in the End Phase the Summoned Grandmaster of the Six Samurai is destroyed because you cannot control more than 1 face-up Grandmaster of the Six Samurai.
- If you select an Elemental Hero Neos Alius that is being treated as a Normal Monster Card and change its name to Elemental Hero Necroshade with Hero Mask, if you Normal Summon the Elemental Hero Neos Alius, so it becomes an Effect Monster, its name will be treated as Elemental Hero Neos.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Edison forum — sourced change requests get reviewed.