Demonic Circle

Demonic Circle consists of two separate spells, Demonic Circle: Summon, which creates the demonic circle, and Demonic Circle: Teleport, which teleports the caster to his demonic circle. There are two main limitations on this spell, one with each half: These limitations mean that a warlock cannot make this spell into a makeshift hearth, although effective application can be very useful.
 * Demonic Circle: Summon, which has a base cast time of .5 seconds, gives the warlock a 15 minute buff which is required to use Demonic Circle: Teleport. This buff is normally removed by timing out, by entering an instance, or through death.
 * Demonic Circle: Teleport, which is an instant cast, is limited by a 40 yd range and a 30 second CD.

One VERY significant use for this spell is in boss fights where the boss casts a nova spell such as Morchok's Black Blood of the Earth. Demonic Circle can effectively be used to move out of range or LoS of the nova up to the last second, taking into account GCD, and allowing warlocks to continue DPS'ing at a point when all other party members are running away. This ability is also useful for use on "Hourglass Duty" on Murozond.

A second powerful use for this ability is in PvP, particularly arenas as the ability removes all snare affects and will move the warlock through walls or obstructions to the demonic circle.

Trivia
Demonic Circle is one of Gul'dan's activatable Talents in Heroes of the Storm. As in World of Warcraft, it consists of two spells, one for placing the Circle, the other for teleporting to it.