The Dark Elixir Storage is a transparent, rectangular-shaped building. It is stated that this storage had to resemble a cube due to the Dark Elixir's power.
6%, 5%, 4% (depending on the town hall level) of the total Dark Elixir in the storage (up to 4,500) can be stolen by attackers, although loot penalties may change this amount (see Raids).
Upgrading your Dark Elixir Storage to a higher level than you require for storage purposes can potentially save Dark Elixir in a raid. As an attacker receives an amount of Dark Elixir proportional to the percentage of damage each hit causes, the higher health of the upgraded building results in less Dark Elixir per hit. It also takes longer to destroy, giving you more time for your defenses to destroy the attacker before they can steal all the available Dark Elixir.
Dark Elixir Storages remain fully functional while being upgraded, like all other Storages.
Due to the low cap on Dark Elixir, it is sometimes difficult to tell if the Dark Elixir Storage is full. For example, a Town Hall 9 player with a level 6 Dark Elixir Storage with just under 36,000 Dark Elixir in the Dark Elixir Storage and just under 7,200 Dark Elixir in the Town Hall (almost enough to reach the 2,500 cap) is less than 20% full and therefore appears empty.
Dark Elixir is the most difficult resource to obtain, with the possible exception of Gems. Consequently, many players protect the Dark Elixir Storage as best as they can.
Prior to this update, there existed an infamous strategy involved using Lightning Spells to damage the Dark Elixir Storage in order to steal some of its Dark Elixir (the Earthquake Spell was introduced in the same update).
Dark Elixir Storages undergo mostly minor visual changes as it is upgraded. The two significant changes occur at levels 3 and 5.
When initially constructed, the Dark Elixir Storage consists of a transparent, slightly rounded cubical storage vessel situated on a four-legged wooden platform. There appears to be a small square opening at the top of the storage.
At level 2, the Storage adds a brass frame to the top of the vessel and a metal spigot at the base.
At level 3, the Storage grows substantially in size, and both the wooden platform and brass frame are replaced by versions made of steel.
At level 4, the Storage gains dark gold legs and a bigger and slightly different tap.
At level 5, the Storage receives spiked steel armor plating on each of the four corners of the base.
At level 6, these armor plates become slightly wider with a pair of small golden spikes on each, and the steel frame atop the vessel turns golden as well.
At level 7, the Storage's armor plates lose their spikes and become smooth blackish-gray metal. The spigot is now made of the same dark metal and has golden accents. There are also gold pieces atop the armor plates.
Although the description refers the Dark Elixir as "three times as powerful", in the game it is in fact 100 times as powerful. This is observed by the Gem cost of buying resources: for example, both 10,000,000 Elixir and 100,000 Dark Elixir can be bought with 3,000 Gems.
It is possible to overflow the Dark Elixir Storage, but only by purchasing special resource packs found in the shop for real money or receiving extra Dark Elixir from the Season Bank. If this is done, any excess Dark Elixir will remain in the storage, and until the excess is removed (either by spending the Dark Elixir or being raided), any Dark Elixir earned from raids will be lost, just as if the Dark Elixir Storage was full.
Tapping this icon displays information about the Dark Elixir Storage, such as Level, Storage Capacity and Hitpoints.
Tapping this icon begins upgrading the Dark Elixir Storage to the next level, if you have enough resources and a free Builder. When the Dark Elixir Storage is at maximum level, this icon is not shown.
Tapping this icon instantly upgrades the Dark Elixir Storage to the next level, at the cost of one Hammer of Building if you have one. When the Dark Elixir Storage is at maximum level, this icon is not shown.
Tapping this icon, which is displayed only while an upgrade is in progress, instantly finishes that upgrade at the cost of the displayed number of Gems.
Tapping this icon, which is displayed only while an upgrade is in progress, instantly finishes that upgrade at the cost of one Book of Building. This icon is only shown if you have at least one Book of Building.
Tapping this icon, which is displayed only while an upgrade is in progress, boosts all your Builders for 1 hour by a factor of ten, at the cost of one Builder Potion. This icon is only shown if you have at least one Builder Potion.
Tapping this icon, which is displayed only while an upgrade is in progress, cancels the current upgrade and refunds half of the upgrade cost.
Tapping this icon completely fills the Dark Elixir Storage, at the cost of one Rune of Dark Elixir. This icon is only shown if you have at least one Rune of Dark Elixir, and if the Dark Elixir Storage is not completely full or overfilled.