Cycnus

Cycnus was the Son of Ares. He lived on a road which many Preist's of Apollo took to get to their temple. He was killed by Hercules.

History
Cycnus lived on the road on the way to a Temple of Apollo. He killed the preists as they pasted and then used their heads to make a temple to Ares.

Meeting Hercules
Cycnus met Hercules and attempted to kill. This was unsuccessful and Cycnus was killed. Hercules was then forced to attack Ares because he killed Ares' son. Ares was wounded but Athena told Hercules not to kill him, which he did not.