Shadowflame

Shadowflame is a Warlock spell of the Destruction tree. It is a Cone AoE ability that affects multiple targets within its reach, dealing direct Shadow damage and a Fire damage-over-time effect to each.

Uses
Shadowflame sees common use in PvP, where it serves as yet another instant cast DoT spell, though it is a close-range AoE and care must be taken not to be within reach of dangerous melee classes such as Warriors. Its DoT is also effective for preventing Rogues from entering Stealth.

In PvE, Shadowflame is a highly potent AoE spell, as well as being useful even in single-target dps. As of 4.1, if already in melee range, it is a DPS gain to use Shadowflame on cooldown in place of normal filler spells for all 3 warlock specs. When used for AoE, it is important to note that while the direct damage follows the standard AoE capping rules (damage capped, before crits, at the damage it would deal to 10 targets), the DoT portion is not and will deal full damage to each target regardless of how many there are. This makes Shadowflame a very good AoE option when there are a significant number of targets.

Boosted with the, the Shadowflame DoT also slows the target. The glyph has notable popularity with PvP Warlocks, and has many uses even in PvE encounters, particularly where controlling mobs is of equal or greater importance than killing them.