Archduke Malorn

Mischief- When Malorn enters the battlefield, look at the top X cards of your library, and put all imps revealed with converted mana cost X or less on to the battlefield, then shuffle the rest into your library, where X is the number of Imps that attacked during your last combat phase.
As long as you control 4 or more imps, Imps you control get +2/+1