Estrid, the Masked is a mythic Legendary Planeswalker — Estrid card from Treasure Chest (PZ2), collector number 70739.
+2: Untap each enchanted permanent you control. −1: Create a white Aura enchantment token named Mask attached to another target permanent. The token has enchant permanent and umbra armor. −7: Mill seven cards. Return all non-Aura enchantment cards from your graveyard to the battlefield, then do the same for Aura cards. Estrid, the Masked can be your commander.