You must destroy 4 idols. These idols are found at the Upper Tier Named random spawn areas (statues of Frogs etc...). Simply stand behind the altars and activate the rock crusher. You must have the Rock Disassembler equipped in order to use it.
The zone in to the instance where the final mob (82^^) is found is in front of where the Avatar of Hate spawns ( -1307, 48, -1509 ) . There is an anvil on the ground near that location, click it to zone into instance. (Only Inquisitors on the same step may enter the instance.)
Return to the Skeleton of Yasva V'Alear to claim your Mythic weapon.
Level 90 Mythical Conversion
Your Mythical Weapon has unique effects which will not work on level 81-90 spells, combat arts, or pets. By completing two quests, you may convert your Fabled or Mythical Epic Weapon into an Enervated Weapon and add persistent Mythical Effect spells to your knowledge book. This allows you to acquire other weapons without losing class-defining Mythical effects.
The quest requires that your class and your Epic weapon match. You will only receive the mythical spell gem of your current class.
You can start this series as long as you have the fabled version of your epic. But if you have completed "Epic Repercussions" then you will not be rewarded the mythical weapon if you go back and complete your class specific Kunark mythical quest.
The quests which make your Epic Weapon effect into a spell is the same for all classes.