Molten Core is a passive warlock ability learned at level 69 for those with the Demonology specialization. Triggered by [Shadowflame] and [Wild Imps'] damage, it reduces the mana cost and cast time of [Soul Fire].
Patch changes
Patch 3.3.0 (08-Dec-2009): Redesigned. This talent now increases the duration of Immolate by 3/6/9 seconds and provides a 4/8/12% chance to gain the Molten Core effect when Corruption deals damage. The Molten Core effect empowers the next 3 Incinerate or Soul Fire spells cast within 15 seconds (Incinerate: increases damage done by 6/12/18% and reduces cast time by 10/20/30%; Soul Fire: increases damage done by 6/12/18% and increases critical strike chance by 5/10/15%). Molten Core now has a new spell effect.
Patch 3.1.0 (14-Apr-2009): This talent has been moved to Demonology (tier-8).