Tengu format ruling
Blackwing - Sirocco the Dawn
Card effect (current official text)If your opponent controls a monster and you control no monsters, 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 total ATK of all "Blackwing" monsters currently on the field, except itself. Monsters other than the targeted monster cannot attack during the turn you activate this effect.
Rulings
- The target gains ATK equal to the ATK of all Blackwings on the field - including your opponent's.
- If the target is set, and then flipped face-up, it doesn't gain any ATK, and you cannot attack with it.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Tengu forum — sourced change requests get reviewed.