Ex, Lorekeeper

Partner with Rin, Soulkeeper (When this creature
enters the battlefield, target player may put Rin
into their hand from their library, then shuffle.)
Defender, Flying
If you would draw a card, you may instead pay {1}. If you do, return target creature card from
your graveyard to your hand.
If Ex would leave the battlefield, their owner
may shuffle it into its owner's library instead.