Creature â Vampire Shaman
When Patron of the Vein enters the battlefield, destroy target creature an opponent controls.
Whenever a creature an opponent controls dies, exile it and put a +1/+1 counter on each Vampire you control.
Patron of the Veinâ€™s last ability puts a +1/+1 counter on each Vampire you control, including itself, even if the creature that died canâ€™t be exiled (most likely because it was a token).
If Patron of the Vein and a creature an opponent controls die simultaneously (perhaps because they fought or were in combat together), Patron of the Veinâ€™s last ability triggers, but Patron of the Vein wonâ€™t be on the battlefield as that ability resolves. It canâ€™t be saved by the +1/+1 counter that would have been put on it. The same is true of any other Vampires you control that die at the same time. Your remaining Vampires will each get a +1/+1 counter.
Destroying a creature with Patron of the Veinâ€™s first ability causes its last ability to trigger if Patron of the Vein is still on the battlefield.