If only your opponent controls a monster, you can Normal Summon/Set this card without Tributing. Once per turn, during your Main Phase 1: You can target 1 “Blackwing” monster you control; until the end of this turn, it gains ATK equal to the combined ATK of all “Blackwing” monsters currently on the field, except itself, also for the rest of this turn, you can only attack with that monster.