This robe is a must for any Sin’dorei’s wardrobe.
Scarlet Sin’dorei Robes, Imbued Netherweave Robe
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Scarlet Sin’dorei Robes
Sunstrider’s Knowledge
Crown of Endless Knowledge, Shoulderpads of Knowledge’s Pursuit, Scarlet Sin’dorei Robes, Black Belt of Knowledge, Exiled Dabbler’s Gloves, (any black boots), Felo’melorn, Talisman of the Sun King
Crimson Pilgrim
Whitemane’s Chapeau, Red Mageweave Shoulders, Scarlet Sin’dorei Robes, Girdle of Prophecy, Black Mageweave Gloves, Sorcerer Slippers, Light’s Wrath (hidden, default tint)
Sin’dorei Scarlet
Whitemane’s Chapeau, Sin’dorei Pauldrons Belt & Slippers, Scarlet Sin’dorei Robes, Shroud of Resolve (rank 6), Light’s Wrath (hidden, default tint)
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Imbued Netherweave Robe
Scryer Illuminator
Helm of Arcane Purity, Elegant Mantle, Imbued Netherweave Robe, Black Belt of Knowledge, Adept’s Gloves, Shadow Council Boots, Scryers Tabard, Staff of Dominance
Kamalia et alia 
I looked at the Scarlet Sindorei Robes and thought “I wonder where that comes from….”
Oh.
It drops from Kael’Thas.
Welp, I’m not gonna see that one.
If I remember correctly, you had to have at least Kara gear, maybe ZA gear to handle Magister’s Terrace at launch.
My BC guild did Kara and ZA pretty successfully. We tried teaming up with another guild to take on SSC and TK and had middling success with it. We never got into Black Temple, Hyjal, or Sunwell. But I do remember running Magister’s Terrace at level, with BTH tanking on his bear and me healing with Kam.
I, of course, solo-farmed that robe for my mage a few expansions later 😛
I remember Magister’s Terrace mostly for my misadventure with Neve when she was leveling, and she ended up in a MgT run with THREE Death Knights, and they took a comment in the group to mean that I was a woman IRL.
Aha! Found it. The title of that post, from way back in 2010, was I Think I Misplaced My Ovaries.
/facepalm