Looter is in four pieces. Use the Golden Key from Whisper's boot to open the golden gates, which show as golden padlocks on the map, and follow each route to a part.
Where to find them
- Legs: high up in Graven Valley.
- Arms: deep inside the Desiccated Castle.
- Torso: deep inside The Drains.
- Head: high up in The Bog, below Queen's Castle. One guide thinks you need Wall Sling to get there.
Take all four back to Whisper's house to rebuild Looter and get a Golden Feather.
Sources: Gamer Social Club 100% walkthrough, MeowDB reference.