Syr Reygmold the Decaying

Last strike
You may cast Syr Reygmold from anywhere,
as an additional cost to cast Syr Reygmold,
exile three cards from your graveyard.
When Syr Reygmold dies, put the top
three cards of your library into your graveyard.
"From a pool of blood, a pile of bones,
or dead flesh, one can summon
the decaying knight"