If you control no monsters and have this card in your hand: You can banish 1 other "Blackwing" monster from your hand; place 1 "Black Whirlwind" from your Deck face-up in your Spell & Trap Zone, then, either send this card to the GY, or immediately after this effect resolves, Normal Summon it without Tributing. You cannot Special Summon monsters from the Extra Deck for the rest of this turn, except DARK monsters. You can only use this effect of "Blackwing - Simoon the Poison Wind" once per turn. During the End Phase, send the "Black Whirlwind" placed by this effect to the GY, and if you do, take 1000 damage.
Simoon is a combo starter, activate Black Whirlwind from your deck to setup a search. You can then Normal Summon Simoon, or send him to the graveyard and Normal Summon a different monster, to trigger Black Whirlwind’s search effect.
With Black Whirlwind you can search a Blackwing Tuner that has a self Special Summoning effect then go into a DARK Synchro monster. If you Normal Summoned Simoon with his effect you will most likely search Blackwing - Oroshi the Squall to make a level-7 Synchro monster.