Defiant Vanguard is a uncommon Creature — Human Rebel card from Nemesis (NEM), collector number 7. Current market price: $0.20 (foil $2.74), TCGplayer market prices via Scryfall.
When this creature blocks, at end of combat, destroy it and all creatures it blocked this turn. {5}, {T}: Search your library for a Rebel permanent card with mana value 4 or less, put it onto the battlefield, then shuffle.