Zhalfirin Commander is a uncommon Creature — Human Knight card from Duel Decks: Knights vs. Dragons (DDG), collector number 13. Current market price: $0.07, TCGplayer market prices via Scryfall.
Flanking (Whenever a creature without flanking blocks this creature, the blocking creature gets -1/-1 until end of turn.) {1}{W}{W}: Target Knight creature gets +1/+1 until end of turn.