Nightwing would be nice for Jon, but DC already has a claim on this one.
How about...

Darkwing? (Not Darkwing Duck..)
Starnight? (Or Starknight)? (begins with S)
Nightstar?
Darkstar?
Solstice? (He's so dark.)

The only known quantity that moves faster than
light is the office grapevine. (from Nan's fabulous Home series)