This is a really standard quest, all you have to do is get the Golden Shell drop from the Beetle Lord who dwells on B1F of the Hall of Darkness. Though the Beetle Lord can be difficult to handle for some as they don't have any weaknesses, you can easily create a weakness with a Runemaster's runes or used any attack that does untyped damage like an Imperial 's Accel Drive or an Arcanist's Dismiss Blast. The Venom Throw skill of the Nightseeker, when maxed out, can also eat up a lot of the Beetle Lord's health without checking its defenses. That'll make short work of them thus making this mission a lot easier and less time consuming!