The Nexus Key

The Nexus Key is an epic two-handed staff for DPS casters.

Source
This item drops from Kael'thas Sunstrider in the Eye.

Patches and Hotfixes
This staff was upgraded to Item Level 141 in patch 2.2. It gained 3 stamina, 1 spell critical strike rating, 7 spell damage and 0.5 DPS.