Ersel, the Foolish King

Knight Convoke (Your Knights can help to cast this
spell. Each Knight you tap while casting this spell
pays one mana of that creature's color.)
{w}, Sacrifice a land: Exile target permanent,
then return it under its owner's control.
{u}, Sacrifice an artifact: Draw a card.
{b}, Sacrifice another Knight: Destroy target
nonblack creature.
''Blind obedience. It is your king's request.''