|Act III - Heliodor, old man in Royal Square||Apollo's Axe|
Return to Heliodor during Act III to find an old man in the Royal Square looking for assistance. He wants you to track down and defeat a monster named Harmachis. Call Cetacea and fly to the Southern Hotto Steppe Whale Way Station.
You'll find a lone Bilwas spawn here (on a quick respawn timer) where you have a chance of encountering the Harmachis. Equip the Ring of Serendipity on the Hero to increase the chances and then defeat it when it appears. Return to the old man to deliver the news and complete the quest.