Nahiri, the Harbinger [Shadows over Innistrad Prerelease Promos] Elf Warrior Add an amount of {B}

Add an amount of {B} equal to the sacrificed creature's mana value

you may pay {X}

By isolating liquid aether at room temperature

target player can't cast instant or sorcery spells

As long as Siege Behemoth is attacking

Nahiri, the Harbinger [Shadows over Innistrad Prerelease Promos] Elf Warrior Add an amount of {B}Set: Shadows over Innistrad Prerelease Promos Type: Legendary Planeswalker Nahiri Rarity: Mythic Cost: {2}{R}{W} +2: You may discard a card. If you do, draw a card. 2: Exile target enchantment, tapped artifact, or tapped creature. 8: Search your library for an artifact or creature card, put it onto the battlefield, then shuffle. It gains haste. Return it to your hand at the beginning of the next end step.