Arwen, Weaver of Hope is a mythic Legendary Creature — Elf Noble card from The Hobbit Commander (HOC), collector number 24. Current market price: $12.05 (foil $15.07), TCGplayer market prices via Scryfall.
Each other creature you control enters with a number of additional +1/+1 counters on it equal to Arwen's toughness.