Radha's Firebrand is a rare Creature — Human Warrior card from Dominaria United Promos (PDMU), collector number 141p. Current market price: $0.04, TCGplayer market prices via Scryfall.
Whenever this creature attacks, target creature defending player controls with power less than this creature's power can't block this turn. Domain — {5}{R}: This creature gets +2/+2 until end of turn. This ability costs {1} less to activate for each basic land type among lands you control. Activate only once each turn.