Alhammarret, High Arbiter
Legendary Creature — Sphinx
Flying
As Alhammarret enters, each opponent reveals their hand. You choose the name of a nonland card revealed this way.
Your opponents can't cast spells with the chosen name (as long as this creature is on the battlefield).
Richard Wright
Magic Origins (ORI)
• #43Rulings
You choose one card name, not one name per opponent.
(wotc • 2015-06-22)
Alhammarret's second ability happens as Alhammarret enters the battlefield. No one can cast spells or activate abilities between the time a card is named and the time that Alhammarret's last ability starts to work.
(wotc • 2015-06-22)
Although spells with the chosen name can't be cast, permanent cards with that name can still be put onto the battlefield by a spell or ability.
(wotc • 2015-06-22)
If your opponents have no nonland cards in their hands, you can't choose a card name. Alhammarret's last ability won't stop any spells from being cast in that case.
(wotc • 2015-06-22)
Your opponents can still cast a card with the chosen name face down if it has a morph ability. A card with the chosen name can also be manifested.
(wotc • 2015-06-22)
Rulings
You choose one card name, not one name per opponent.
(wotc • 2015-06-22)
Alhammarret's second ability happens as Alhammarret enters the battlefield. No one can cast spells or activate abilities between the time a card is named and the time that Alhammarret's last ability starts to work.
(wotc • 2015-06-22)
Although spells with the chosen name can't be cast, permanent cards with that name can still be put onto the battlefield by a spell or ability.
(wotc • 2015-06-22)
If your opponents have no nonland cards in their hands, you can't choose a card name. Alhammarret's last ability won't stop any spells from being cast in that case.
(wotc • 2015-06-22)
Your opponents can still cast a card with the chosen name face down if it has a morph ability. A card with the chosen name can also be manifested.
(wotc • 2015-06-22)