Throwing Down

Legendary creature spells you cast have convoke.
(Your creatures can help cast those spells. Each
creature you tap while casting a legendary creature
spell pays for {1} or one mana of that creature's
color.)
Whenever your commander attacks, create a 1/1 red Mercenary creature token with "{t}: Target crea-
ture you control gets +1/+0 until end of turn.
Activate only as a sorcery."