Seath, the Scaleless

Seath, the Scaleless cannot be countered.
When Seath enters the battlefield, target player
exiles all dragon creatures he controls.
If 3 or more creatures were exiled this way, Seath
gets 0/+3 counter and Scry 3.
{u}{u}{b}{b}: Deal 3 Damage to all creatures on the battlefield, except himself.
"Betrayed his own kind."