Wernog, Rider's Chaplain is a rare Legendary Creature — Human card from Universes Within (SLX), collector number 8. Current market price: $1.24, TCGplayer market prices via Scryfall.
When Wernog, Rider's Chaplain enters or leaves the battlefield, each opponent may investigate. Each opponent who doesn't loses 1 life. You investigate X times, where X is one plus the number of opponents who investigated this way. Partner—Friends forever (You can have two commanders if both have this ability.)