Blackwing - Sirocco the Dawn [CRMS-EN010] Common

If your opponent controls a monster and you control no monsters, you can Normal Summon or Set this card without Tributing. Once per turn you can select 1 Blackwing monster you control. It gains ATK equal to the combined ATK of all other face-up Blackwing monsters. If you use this effect, your other monsters cannot attack this turn.