Viridian Betrayers is a common Creature — Phyrexian Elf Warrior card from New Phyrexia (NPH), collector number 124. Current market price: $0.19 (foil $1.56), TCGplayer market prices via Scryfall.
This creature has infect as long as an opponent is poisoned. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)