Elrond, Lord of Rivendell

When Elrond, Lord of Rivendell enters the battlefield, look in your library for a card named Rivendell and put in your hand.
First strike, reach.
Sail to Valinor - Exile any number of Elves from
your graveyard. Until end of turn, legendary
spells you cast cost X less to cast, where X is the
number of Elves exiled this way.