Retrieve the Stenz from the Splintery Chest.
Trade the Stenz to the Magian Moogle and select Trial 710 to start the quest. Your Stenz will be augmented with [Trial 710].
Kill Stray Mary three times in Konschtat Highlands with the Stenz equipped.
Each kill will be recorded and displayed for confirmation.
After trading the Stenz to the Magian Moogle you will be rewarded with the Rageblow.