Answer:
Agamemnon
Explanation:
'Atreus' son' and 'lord of men' both refer to Agamemnon, and Achilles is called 'glorious'. Epithets serve as a kind of shorthand to immediately identify the hero or thing being described: so Agamemnon can be described in terms of his birth right ('son of Atreus') or his role ('lord of men').