If you become a shadoweave specialist, you will make twice as much shadowcloth as an average tailor and have access to several exclusive patterns.$B$BOf course, any tailor can use the Altar of Shadows, but a shadoweave tailor possesses a deeper attunement to the altar, unlocking powers that few can fathom.$B$BTake this crystal to eastern Shadowmoon Valley, and find Netherwing Pass leading south from the Netherwing Fields. Near the world's edge, you will find the Altar of Shadows. Use the crystal there.