Blackwing - Decay the Ill Wind (SHVI-EN017) (SHVI)

Once per turn, during the End Phase, if this card is in the Graveyard because it was sent there this turn: You take 1000 damage. When this card is Normal or Special Summoned: You can target 1 "Blackwing" monster you control, then activate 1 of these effects;
- Increase that target's Level by 1.
- Reduce that target's Level by 1.
You can only use this effect of "Blackwing - Decay the Ill Wind" once per turn.