Sona, Gitaxian Operative

Ward —{2}, Discard a card.
{u}{b}, Discard a card: Create a Forerunner Role
token and attach it to target creature you control.
(If you control another Role on it, put that one into
the graveyard. Enchanted creature gets +1/+1 and
has "At the beginning of your upkeep, sacrifice a Role attached to this creature and draw a card.")
Partner