[EDIT 9/15: Patch 2.0 had an unlisted change to The Hunger. The duration bonus provided by that skill or Skull of Dire Ahamkara has been doubled to 6 seconds, giving a total energy drain duration of 11 seconds when this skill or exotic armor piece is used. This means the grenade cooldown reduction with longer duration energy drain is 6.6 seconds per effect triggered. If you have double grenade charges, such as through the Nothing Manacles, then the cooldown reduction is 13.2 seconds on the second grenade since energy drain is a multiplier and bonus charges on abilities take twice as long to cooldown as a single charge] I posted this to reddit some time ago due to the general misunderstanding of how this ability and the associated buff effect and synergy upgrades work. Since the topic comes up in these forums as well I thought it best to replicate it here. [url=http://redd.it/2lzh0r]link[/url] The original text is reproduced below for those who may not be comfortable following links: This is one of the more misunderstood effects in the game--and understandably so given how little information we are given in most RPGs. This topic comes up very frequently on here, bungie.net and many other Destiny related forums. As there is a great deal of misunderstanding and greater misinformation out there, it felt best to detail this effect and ability in one single and extensive thread. The first part deals purely with the Energy Drain effect alone, whereas the full attributes of the Energy Drain melee are detailed separately at the end of this thread--for reasons that will be apparent later. The information here is culled from various sources, with numbers gleaned from the Official Strategy Guide and patch notes, and then confirmed through exhaustive and thorough in-game testing with many variables. ENERGY DRAIN: the EFFECT The Energy Drain effect is a short duration 'buff' that accelerates a Voidwalker's rate of grenade energy recharge per second for that duration. This is primarily applied when using the Energy Drain melee attack, though it also can be applied through grenades and Nova Bomb if the Embrace the Void ability is selected. The base duration is 5 seconds. This duration can be increased to 8 seconds by either taking The Hunger ability or through the Delusions of Grandeur perk of the Skull of Dire Ahamkara. These duration increases do not appear stack. This non stacking of duration increases may either be a glitch, or it may be the case that the The Hunger ability is actually granted by this armor piece and the description was never updated/clarified to reflect this. The Official Strategy Guide lists the multiplier to the grenade recharge rate at x1.6 for the duration of the energy drain effect. A far simpler way to express this is: ED duration x 0.6 = grenade cooldown reduction. Both the duration and the effective cooldown reduction are measured in seconds in this formula. In either case, regardless of your Discipline score an Energy Drain effect will always reduce your grenade cooldown by 3 seconds on its own or 4.8 seconds with the duration increase from The Hunger or the Skull of Dire Ahamkara. This makes it far more rewarding on a Discipline focused build as it allows your grenades to consistently recharge faster than other characters, especially when you chain multiple instances of this effect during the cooldown. Multiple energy drain effects can be triggered back to back over the course of the grenade, further reducing the cooldown each time. However simultaneous energy drain effects do not stack, and the durations will neither refresh nor overlap if a new effect is triggered before the previous one wore off. So for a build focused on this skill the use of your cooldown abilities should be spaced 8 seconds apart, or simply wait for the flashing buff to disappear. Embrace the Void will trigger the energy drain buff anytime you hit with a grenade or Nova Bomb in addition to your melee. This is what enables you to chain multiple energy drain effects over the course of a grenade cooldown, giving you dramatically faster and consistent grenade replenishment compared to other subclasses. Note that Embrace the Void will NOT trigger the upgrades to your energy drain melee attack (Surge, Lifesteal, and Soul Rip) as they are exclusive to the melee ability. The same applies to the Touch of Flame of Sunsingers; it only triggers the Ignite side-effect effect of Scorch but not its melee exclusive Flame Shield or Brimstone upgrades. If these abilities triggered melee upgrades on every grenade hit then it would severely undervalue STR bonuses and simultaneously make Embrace the Void/Touch of Flame the most overpowered options for those subclasses. So in breakdown: Energy Drain effect : x1.6 multiplier to grenade recharge for 5 seconds The Hunger: increases duration by 3 seconds Delusions of Grandeur: essentially gives you 'The Hunger' Embrace the Void: applies the Energy Drain effect to grenade and Nova Bomb hits. ______________________________ ENERGY DRAIN, the MELEE ability Now this ability has additional properties of its own, in addition to triggering the energy drain effect. Base damage: 110 void (modified by Light bonus and level differences) Range: 6m (according to OSG. Or simply x1.5 your basic melee range) Effects: triggers the energy drain buff (see above) Upgrades: the melee attack can trigger one of three selected upgrades upon hit/kill. Once again, these upgrades only apply to the melee ability itself and are NOT triggered through Embrace the Void. Surge: upon a hit this upgrade maximizes your weapon handling stat and increases your Agility to the maximum of 13 for 15 seconds. Lifesteal: upon a kill this upgrade instantly heals 10 points of damage and gives 1.5 seconds of health/shield regeneration. This regeneration occurs even if you are actively taking damage, and is capable of bringing your shields up to full if no damage is taken. Soul Rip: upon a kill this instantly replenishes 10% of your super meter bar, in addition to the normal super meter gains from a kill. Note that the 10% super meter gain is not displayed in white like other kills, but rather it causes the gray portion of the super meter to 'jump' forward 10%. The displayed white portion of the bar is only the normal super energy gained from the kill itself. Hopefully this clears up both misunderstandings and sheds some light on the exceedingly vague descriptions of abilities we receive in modern RPGS. [i][/i]