Sisay, Weatherlight Captain is a rare Legendary Creature — Human Soldier card from The List (PLST), collector number MH1-29. Current market price: $2.82, TCGplayer market prices via Scryfall.
Sisay gets +1/+1 for each color among other legendary permanents you control. {W}{U}{B}{R}{G}: Search your library for a legendary permanent card with mana value less than Sisay's power, put that card onto the battlefield, then shuffle.