Possible Clues:

• Son of Clytemnestra and Agamemnon
• See sort that could turn out murderer in mythology
• Classical matricide finds drug in fashion stores
• The Furies pursued him
• Son of Agamemnon taking ecstasy into the woods, heading off
• Matricide beheaded enemies without respite
• Hero of 20-Across
• Mythological brother of 63-Across
• Love remains to ensnare European hero of drama
• Co-avenger with Electra