The potion is located on one of the tables in the The Vaults of El'Arad in the Library of Arcane Research and Teleportation. Reported locations include: 42, 0, 133 , 67, 0, 80 and 68, 0, 123 .
Once you have the Sebilis Slave Mine Map you can click a rock at -191, -113, 403 in the Reet Slave Mine and it will send you to the Reet Resistance Cave.
Clicking the rock will take you into a solo instance and you will not be able to take your team with you. You must disband from your group or it will not let you zone into the instance.
Just keep heading in to the mines to find the rock. At the tunnel that splits left and right, left goes to spore king, right goes to your rock. Hug the left wall and you will see it. It is in a large room roughly underneath the slave quarters in the mines. The rock is on the left as you enter the room from the area with the mushroom and dog mobs.
Inside the instance examine the Ensorcelled Boot to summon the frog from upstairs. Talk to him and he tells you to talk to his leader, Captain Rroop. This completes A Reet's Freedom. Do NOT leave just yet, the quest continues. Captail Rroop takes a scouts report while you're there, listen the the report. After listening to the report you will be asked to kill 12 iksars in the instance.
Go to the Kunzar Jungle and fly to The Abandoned Village. From there, walk east until you see an ethereal sword sticking out of the ground ( -643,21,-162 ) . You will be stunned at -694.68,38.95,-225.50 and it will initiate a conversation between you and a spirit, which tells you to find the paladin epic weapon, The Truth of Marr.
Izzal tells you a bit more lore and informs you that the iksars have been using an item of malevolence to inflict pain in their worship of Cazic-Thule.
Somewhere in Kunark find an Item of malevolence being used by the Iksar.
You will immediately be attacked by a ring event of ^81 monks that concludes with Grandmaster Kordaz. He stuns a lot and is very difficult to solo so, you will want to bring friends. If you fail you LOSE your Mark of Terror and must get another!
After Grandmaster Kordaz is dead, talk with a Swifttail caste servant again and she will send you to the Monk Temple of the Grandmasters at Tabernacle and loot the Malevolent blade. ( -110,-39,190 )
Izzal was amazed at the weapon that I obtained at The Tabernacle of Pain.
He explained that it is the reformed metal tablets that once held the tenants of Marr, it The Truth of Marr spent a detrimental amount of time within the demi-plane The Sphere of Malevolence, and as a result of that time it has become corrupted.
He believes that there must be a way to cleanse the sword and restore it to its prior glory.
Inspect a ring after you get all 3. Head back to Izzal Din and you're done!
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.