Blackwing - Sirocco the Dawn (CRMS-EN010) - Crimson Crisis Unlimited

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.