Onyx Embedded Leggings are mail leg armor with a large amount of Shadow resistance and a hefty amount of Agility, Stamina, and Intellect..
Onyx Embedded Leggings is a quest reward from the quest Nefarius's Corruption which starts with Vaelastrasz the Corrupt in Blackwing Lair in Blackrock Mountain.
The questline to obtain these is for the [Red Scepter Shard], which is for [The Scepter of the Shifting Sands].
Patches and hotfixes
Patch 1.9.0 (03-Jan-2006): Added