Quest #085 Comeback Kid - Swinedimples Academy
Quest Requirements: Defeat a Metal Slime with Power Throw then witness a scene west of Swinedimples
Quest Pre-Requirements: 30 Skill Points in the Boomerang Skill Tree
This quest begins by speaking with a kid in the southwestern courtyard of Swinedimples Academy. In order to accept this quest you'll need at least 30 Skill Points spent in the Boomerang Skill Tree on any of your vocations.
For this quest you have to defeat a Metal Slime enemy with the Boomerang Power Throw ability. You can find the Metal Slimes that you need for this quest in Quarantomb which is west of Coffinwell. If you haven't already unlocked the Armamentalist class, it's a quest that has you defeat Metal Slimes in the same area and would be worth doing at the same time. Follow the link for more information about how to get to Quarantomb and tips for finding the Metal Slimes inside.
Slime Hill is a location you can only access with the Starflight Express near Angel Falls. For more information on how to get to Slime Hill check out Side Quest #055; it requires you to visit the boy in the cave right here and I go into more detail about how to get here.
If you'd like to try out Slime Hill, it's an area with a ton of regular slime enemies and an occasional metal slime enemy. Any type of metal slime enemy can spawn on this hill and a lot of the hill is covered in forest so they can be difficult to see too, which is arguably the biggest downside.
Anyway, once you've defeated the Metal Slime enemy there is still more we have to do before we can officially call this quest complete. Return to the kid in Swinedimples Academy who gives you this quest and he'll give you a boomerang and tell you to go west and wait by the bridge. Use Sterling's Whistle and fly to Urdus Marshlands in the west - the bridge you need to stand on is shown in my screen shot above.
There'll be a lady waiting for you at this bridge, approaching it will trigger a scene and when you're done you'll want to return to the boy at Swinedimples Academy.