Shade, Echo of Regret

Shade, Echo of Regret begins the game in your
graveyard if it is a commander, and its power is equal to
the number of creature cards in your graveyard.

When a creature named The Knight dies, return Shade
from your graveyard to the battlefield.

When a creature named The Knight enters, sacrifice Shade
and create a Treasure token.

Partner with The Knight, Perfect Vessel