Warden Of Portals

Warden Of Portals costs {1} less to cast for each creature your opponents control.
Flying.
{1}{w}: Exile target nonland permenent, then
return it to the battlefield.
{1}{u}{u}: Return target creature to it's owner's
hand.
{1}{b}{b}{b}: Exile target nonland permenent until
Warden Of Portals dies.