Serpent Charmer

Darkness (This ability is active if cards have been put into your soul during this turn):If the number of cards in your soul is ten or more, this unit gets +2000. If the number of cards in your soul is fifteen or more, this unit gets ":[Retire this unit] At the end of your turn, you may pay the cost. If you do, choose thirteen cards from your soul, return the rest of your soul to your deck, shuffle your deck, and draw a card.".