Elystra, Dark Sorceror

+1: Add 1 mana of dark energy to your mana pool. This mana doesn't empty out at the end of your turns.
-3: All dark energy in your mana pool becomes stable. (Note: This card can be your commander).
-6: Create a 0/0 colourless Dark Energy Artifact Creature token with "This creature gets +1/+1 for each dark energy in your mana pool".