Cavalry Master is a uncommon Creature — Human Knight card from Time Spiral (TSP), collector number 6. Current market price: $0.16 (foil $0.66), TCGplayer market prices via Scryfall.
Flanking (Whenever a creature without flanking blocks this creature, the blocking creature gets -1/-1 until end of turn.) Other creatures you control with flanking have flanking. (Each instance of flanking triggers separately.)