This cannot be placed in a defense zone.

"Battlefield of the Void":While you have 1 or less different (A7) cards in your graveyard, this has 3 STK and Retallate.

"It's a Wonderful World": While you have 7 or more different (A7} cards in your graveyard, this has 5 STK.

(A7) unit cards in your hand have Sentinel Summoning.