Elend, King of Luthadel

Partner with Vin, Lady Heir (When this creature
enters to the battlefield, target player may put Vin
into their hand from their library, then shuffle.)
Spells your opponents controls that targets you
cost {1} more to cast.
Whenever Elend, King of Luthadel is dealt
dammage, exile him then return him to the battlefield transformed under his owner's
control. If you do, create a Treasure token.