The Mightstone and Weakstone [The Brothers' War Prerelease Promos] Historicbrawl sacrifice it and you gain

sacrifice it and you gain 4 life

It was an ancient defense of the Dwarves that could only be traversed in single file

"If powerstones are energy stored in material form

Set: Secret Lair Drop Series Type: Legendary Creature — Elf Ally Rarity: Rare Cost: {2}{R}{G} You may play an additional land on each of your turns

If a legendary permanent or an artifact entering or leaving the battlefield causes a triggered ability of a permanent you control to trigger

The Mightstone and Weakstone [The Brothers' War Prerelease Promos] Historicbrawl sacrifice it and you gainSet: The Brothers' War Prerelease Promos Type: Legendary Artifact Powerstone Rarity: Rare Cost: {5} When The Mightstone and Weakstone enters the battlefield, choose one Draw two cards. Target creature gets 5 5 until end of turn. {T}: Add {C}{C}. This mana can't be spent to cast nonartifact spells. (Melds with Urza, Lord Protector.)