Decreases the cooldown of your Fade ability by X seconds, and reduces the cooldown of your Shadowfiend ability by Y minutes.
Veiled Shadows is a Shadow talent that reduces the cooldown of the priests Fade and Shadowfiend abilities.
This talent is useful for PvE mainly for its reduction of cooldown on the Shadowfiend ability. With threat being practically a non-issue in the current game, the reduction of Fade in PvE becomes less attractive but if a priest finds themselves with mana issues, the reduction in Shadowfiend would be useful.
The reduction in cooldown of Fade is a useful component in PvP environments since Fade now provides mobility and escape. Being able to escape more often can save ones life.