Back in the Theros days, players could play the Hero's Downfall, a removal spell, which would deal with both creatures and planeswalkers for only three mana.
It looks like Swift End is basically the same card, but with a slight drawback: it loses two points of life. But this is not a simple card. Instead, it's an adventure card, which lets you summon a creature from exile after casting Swift End.
That creature will not only bring back two points of life, but it will also pose a repeatable threat since it can't die.