Dark Eruvian

This spell costs {w}{u}{b}{r}{g} less to cast if you
control your commander. (This effect only
applies to colored mana.)
When Dark Eruvian enters the battlefield, you
may search your library for a card named
"Clevra, Bound to Eruvian" and put it onto the battlefield tapped.
At the beginning of your end step, proliferate.
{t}: Add {w}{u}{b}{r}{g}