Karina, the Veiled Blade

Double Strike, Haste, Vigilance
Eminence -- Whenever you cast an enchantment
spell, if Karina, the Veiled Blade is in the
command zone or on the battlefield, Karina, the
Veiled Blade gets +3/+3 and cannot be blocked.
Whenever Karina, the Veiled Blade attacks, each opponent discards card.