Purity

Purity typically isn't a very good card, as it requires you to exhaust cards that you've already drawn. By removing 3 cards with a Purity, you've effectively lost 4 drawn cards just to make your deck smaller. That said, it has fantastic synergy with , as it allows you to exhaust useless attacks/defends that were clogging up your hand. It can also be good if your deck is almost able to go infinite, or if your deck is full of card draw.
==Update History==
*Weekly Patch 46: Adrenaline
**Purity card wording improvements.
*Weekly Patch 8: Ooh Shiny!
**Purity card rework. 2 cards -> 'up to' 3 cards -> 5 cards on upgrade.