For those who doesn't know what am I talking about, please follow the guide step by step, for others, who already have their epic cloaks jump to the last chapter.
Chapter I: Trial of the Black Prince
After you reach level 90, NPCs from major cities of Pandaria will give you the first quest of this big quest chain. Stranger in a Strange Land, will ask you to meet Wrathion in the Tavern in the Mists in The Veiled Stair. Remember this location since you'll go there most of the time Wrathion has something for you.
After a quick chat you'll have to start farming reputation with the Black Prince. You need to be Honored with him to go further. You can use the Reputation Calculator to track your progress and see what's optimal for you to farm. Keep in mind that you don't need to start this quest chain in order to gain reputation with the Black Prince.
The next step is when you have to farm 10x Sigil of Power and 10x Sigil of Wisdom. Those items drop from Mogu'shan Vaults, Heart of Fear and Terrace of Endless Spring bosses. These items can also drop from Throne of Thunder Bosses and Siege of Orgrimmar first 8 bosses as well. You can farm them in any raid difficulty.
The last step of this chapter requires you to kill the Sha of Fear and loot the Chimera of Fear.
The reward for this chapter is one of the Legendary Gem. You can place these games only on sha touched weapons (the weapons with Sha-touched sockets). You can always buy a new legendary gem for 10k gold.
Chapter II: Wrathion's War
The first step of this chapter requires you to "farm" 3000 valor points (this will take you three weeks to complete). You can spend the points while on this quests and keep in mind that gaining valor after weekly cap wont help the progress.
The next quest will ask you to farm more reputation with the Black Prince and get revered with him. You can do this before farming those 3k valor points if you like to speed things up a little bit.
The Black Prince will ask you to test your PvP skills now and send you to Temple of Kotmogu and the Silvershard Mines. You need one victory in each of these BGs.
The alliance players will have to kill Warlord Bloodhilt and the horde High Marshal Twinbraid for the last test of this chapter. Get some friends to help you with these guys...
The reward of this chapter is the Eye of the Black Prince. This item will add a Sha-touched socket to your weapon allowing you to use the legendary gems on any weapons now. There are some limitations though: those sockets are unique, you can buy a new eye for 2.5k gold and you can't use the eye on Siege of Orgrimmar and heroic scenario weapons.
Chapter III: Two Princes
Right from the start of this chapter, you'll be given two quests. One will require Exalted reputation with the Black Prince and the other to farm a bit more. This time you need 20x Secrets of the Empire and 40x Trillium Bar. The bars can be bought or made by miners or alchemists and the legendary items drop from Throne of Thunder bosses (on all difficulties). Lei-Shen has a 100% drop chance. These items drop from the first 8 bosses of Siege of Orgrimmar raid as well.
Next quest, The Thunder Forge, will send you to the Isle of Thunder on a solo scenario. Don't take this scenario lightly...
Nalak is the next enemy you need to slay, use Lightning Lance on him, before he dies, and kill the add that spawns by kiting him around.
The reward of this stage is one of the legendary meta gem. You can place these gems in any head meta socket, but the helm needs to be above iLevel 502. You can buy additional gems for 5x Primal Diamonds.
Chapter IV: Celestial Blessings
After you defeat Lei-Shen, you'll need to collect 12x Titan Runestone. These drop from the last six bosses of Throne of Thunder and the first eight bosses of Siege of Orgrimmar. Lei-Shen had a 100% drop chance.
After this you'll have to visit all the Celestial Guardians of Pandaria and defeat one of it. The one designed for your spec/role. Don't take this lightly either...
The reward of this chapter is an epic iLevel 600 cloak. You can buy an additional cloak fro 100k gold.
Chapter V: Judgment of the Black Prince
This is the last chapter of this epic series of quests.
Wrathion sends you to the Timeless Isle and ask you to collect 5000x Timeless Coin. These drop from Timeless Isle mobs, chests and are rewarded from quests. Even if the number seems big, it wont take long.
The Emperor's Way is the following quest. You'll have to defeat the four world bosses. All those bosses are present on Timeless Isle and you'll need a raid to kill them.
The reward is Timeless Essence of the Black Dragonflight which will make your cloak legendary.
To complete the Chapter V achievement as well you'll need to kill Garrosh too.
Here these are the cloaks you can get: Qian-Le, Courage of Niuzao, Qian-Ying, Fortitude of Niuzao, Xing-Ho, Breath of Yu'lon, Jina-Kang, Kindness of Chi-Ji, Fen-Yu, Fury of Xuen and Gong-Lu, Strength of Xuen.
Even if you haven't start this quest chain of even if you just start playing Mists of Pandaria, it's pretty easy to catch up. The 5.4 patch will allow you to farm all those legendary tokens from Siege of Orgrimmar as well, making this pretty cool and much faster.
If I remember correctly, this is the first quest chain that lasted from the beginning of an expansion till the end of it, making it really unique and epic. There is a lot of lore in it and if you like a good story you should try it. Well, the rewards are nice a well...
If any of you have more hints or thoughts regarding these quests, leve your comments below.