Regeneration is the ability for a unit or building to self-heal their hit points without the need of a healer, first introduced in Age of Empires II. Units with regeneration are valuable in pitched battles and often essential in campaign scenarios where the player cannot build a base and train units, but has to fight their way through with a starting army.
A unit with health regenerative abilities will receive even faster healing when stacked with other sources of healing.
Age of Empires II
In Age of Empires II, there are a few units that can regenerate, most notably the Berserk. With the release of The Conquerors all heroes gain a regeneration ability, making them very valuable in campaign scenarios. Often, heroes are also must-survive units, and the regeneration ability aids the player greatly since they can actually use the heroes in front line battles instead of just having to protect them.
Among regular trainable units, regeneration is a fairly exclusive trait. The Berserk is the only unique unit to have an innate regeneration ability, which can be furthered by researching Berserkergang. Berber camel units (Camel Riders and Camel Archers) gain a regeneration ability once Maghrebi Camels is researched.
- Heroes: 40 HP per minute
- Berserk: 20 HP per minute (40 HP per minute with Berserkergang)
- Berber camel units: 15 HP per minute (after researching Maghrebi Camels)
- Polish Villagers: 5/10/15/20 HP per minute (in the Dark, Feudal, Castle, and Imperial Age, respectively)
Age of Mythology
In general, regeneration is a more expanded feature in Age of Mythology, with several major and minor gods having access to certain regeneration-related features. When a unit has finished regenerating, it will briefly shine a green hue (see gallery).
God bonuses and technologies
Gaia enables buildings to slowly regenerate HP/second.
- Hephaestus Revenge (Leto) enables Automatons to regenerate 1.0 HP/second.
- Heroic Renewal (Hyperion) enables heroes to regenerate HP/second.
- Mythic Rejuvenation (Hekate) enables myth units to regenerate 2.0 HP/second.
- Acupuncture (Nü Wa) enables Peasants to regenerate 0.5 HP/second.
- Elixir of Immortality (Chang'e) enables Immortals to regenerate 2.0 HP/second.
- Colossus (Hephaestus) can heal themselves by eating gold or trees. The rate is HP/second.
- Wadjet (Ptah) regenerates 1.0 HP per second.
- Troll (Forseti) regenerates HP equal to the damage it causes.
- Behemoth (Rheia) regenerates HP/second.
- Jiangshi (Zhong Kui) regenerates by fighting, similarly to the Troll. The rate is
Additionally, all campaign heroes (Arkantos, Amanra, Zhi, etc.) slowly regenerate, similarly to Age of Empires II, but don't die, unlike in Age of Empires II. Instead, when they reach 1 HP, they collapse and have to be revived by having friendly units approach them.
There are other units and buildings found in the campaigns that demonstrate the ability to regenerate HP. In the Fall of the Trident campaign, the Living Poseidon Statue from the A Place in My Dreams scenario regenerates HP at tremendous speed. Only Arkantos in his demi-god form, who also regenerates quickly, can destroy it.
In The New Atlantis campaign, various Titans demonstrate an ability to quickly regenerate as well. These include Prometheus in Betrayal at Sikyos and Kronos and Gaia in War of the Titans. The Tower of Odin is a special Wonder that regenerates at such a high speed that the only way to get rid of it is with the Deconstruction Wonder god power.
Age of Empires III
In Age of Empires III, passive idle regeneration is based on a percentage of a given units maximum hit points with a activity lockout in seconds before they can begin regeneration. The activity lockout takes effect if the unit takes any action, including walking, training and building, as well as attacking other units. Simply being attacked does not stop regeneration, meaning with enough maximum hit points a unit can regenerate faster then they are being damaged if they are in stand ground stance and not attacking. The formulae can be found in the civs.xml in the data folder if you unpack the data.bar. With update 29715, an icon for the passive regeneration ability has been added in the ability panel for units that can regenerate.
Heroes (such as Explorers, Daimyo and War Chiefs) remain the most notable units that slowly regenerate at a rate of 0.25% maximum hit points every second, after an activity lockout of 3.5 seconds. SPC units in campaigns instead heal for either 0.5% or 0.65% maximum hit points a second. Similar to Age of Mythology, they collapse once their HP reaches 1, but unlike in Age of Mythology, their hit points don't stop regenerating when they have collapsed.
Other units notable for being the only non-hero units to regenerate are the Spahi, which are available to the Ottomans, and the Gurkha, which are available to the Indians. Gurkha and their Mansabdar counterpart regenerate at 0.25% maximum hit points per second with a 3.5 activity lockout like hero units, while Spahi uniquely regenerate 2% maximum hit points a second with a 2 second activity lockout. Minutemen class units degenerate at a constant 2% maximum hit points a second, effectively losing hit points every second until their hit point bar reaches zero. Naval units that idle near docks also regenerate; however, that regeneration is a flat amount and does not scale with maximum hit points. Instead, naval units regenerate 2 hit points a second, increasing to 4 hit points a second with the Advanced Dock card.
These units can regenerate conform to the above-mentioned mechanics:
- Campaign heroes
- Explorer Dog
- War Chief
- Skull Knight (since update 23511)
- Shaolin Master
- Gurkha (before the Defintive Edition)
- Mansabdar Gurkha (before the Defintive Edition)
- Urumi (since the Defintive Edition)
- Mansabdar Urumi (since the Defintive Edition)
- Shogun Tokugawa