Kayden, Awakened Horror

Double Strike, Vigilance
Extend Combo - Kayden gets +X/+X where X is twice the number of times Kayden has attacked this turn
Extra Rounds - Whenever Kayden deals combat damage to a player you may pay {r}{w}{b} if you
do, there is an additional combat phase after this one. Activate only once per opponent

"You've awakened your slumbering nightmare. I'm
not sorry for what I have to do now."