Northern Air Temple is a uncommon Legendary Enchantment — Shrine card from Avatar: The Last Airbender (TLA), collector number 111. Current market price: $0.28 (foil $0.34), TCGplayer market prices via Scryfall.
When Northern Air Temple enters, each opponent loses X life and you gain X life, where X is the number of Shrines you control. Whenever another Shrine you control enters, each opponent loses 1 life and you gain 1 life.