Uroboros, Gyre of Torment

Discount: You may [Put 2 cards from your hand on the bottom of your deck.] to instead pay a cost of 2 to play this.

As you summon this from your hand, reduce its cost by the number of allied Exader units in play. Retaliate.

"Essence Devour": When this destroys an enemy unit through combat damage, add the destroyed unit underneath this as a charge (including units destroyed by this unit's Retaliate).

"Voidlight Halo" - Turn 1 - Instant Action: [Put 1 or more of your charges on the bottom of its owner's deck.] Choose 1 card in play of a level equal to or less than the number of charges you moved for this ability's cost. Destroy that card.