This Mote of Shadow farming guide will show you the places that I use for farming Mote of Shadow. There were no major changes to Mote drop rates at Outland, so this guide can be used for Burning Crusade Classic (TBC) and Retail WoW.
Primal Shadow comes from combining 10 Mote of Shadow, so if you need Primal Shadow, you have to farm Mote of Shadow.
Mote of Shadow
This farming place is for Retail WoW players only. If you play Burning Crusade Classic, scroll down a bit for the other farming places. But, for retail players, this is the best farming place. They can ignore the rest of the guide. (assuming you have a high-level character)
The Arcatraz is located East of Netherstorm, it's near the raid instance Tempest Keep. You will see 3 platforms floating in the sky, Arcatraz is the highest floating platform, considerably higher than the others. (picture of the entrance) There will be bars on the instance entrance, just simply click to unlock them.
One run takes 2-3 minutes and you get around 9-12 Mote of Shadow.
After you killed the mobs, go outside and reset the Instance by right clicking over your own portrait then click the "Reset all instance" button. This restarts the whole instance and all mobs will be back. You can only reset an instance 10 times in an hour.
You can farm Mote of Shadow at Void Ridge in Hellfire Peninsula. There is a lot of Vacillating Voidcallers and Collapsing Voidwalker at the marked location, they all have really fast respawn time, so you can farm here without downtime.
You can also farm Voidspawns around Oshu'gun in Nagrand. These are a bit higher level than the mobs at Hellfire, but the drop rate is also higher.