Here is a good ol' reprint of the card that can wreck some havoc in the Boros (red-white) decks. If you have a card on the battlefield with the Mentor ability and at least three points of power, then whenever Skyknight Legionnaire attacks it'll get the +1/+1 counter.
This means that it'll potentially keep growing as it attacks, which means a swift victory for you. But this should be no surprise, as Boros color pair has always been one of the most aggressive combinations in the history of Magic: The Gathering.
