Meta Magic

Your Commander is a Sorcerer in addition to its
other types. You may choose a Sorcery instead of
your background. The Sorcery is Legendary.
(You may cast a Legendary Sorcery only if you
control a Legendary Creature or Planeswalker.)
(Your Commander must have the "Choose a
Background" ability.)
Sorcerers you control gain Bloodline Magic:
Instant and Sorcery Spells you cast cost {1} less to
cast.