Warden of the Inner Sky is a rare Creature — Human Soldier card from The Lost Caverns of Ixalan (LCI), collector number 359. Current market price: $0.36 (foil $0.52), TCGplayer market prices via Scryfall.
As long as this creature has three or more counters on it, it has flying and vigilance. Tap three untapped artifacts and/or creatures you control: Put a +1/+1 counter on this creature. Scry 1. Activate only as a sorcery.