A tank is a style of character in gaming, often associated with a character class. A common convention in real-time strategy games, role-playing games, MMORPGs, MOBAs and MUDs, tanks redirect enemy attacks and/or attention toward themselves in order to protect other characters or units. Since this role often requires them to suffer large amounts of damage, they rely on large amounts of vitality or armor, evasiveness and misdirection, and/or self regeneration.
Tanks are often represented as large or heavily armored.
Role in games 
"Tanking" occurs when the unit is intended to be the one taking damage (typically by being dangerous or detrimental, or using a game mechanic that forces it to be targeted), and secondly, to ensure that they can survive this damage through sheer health points or mitigation.
In real-time strategy games the role of a tank unit is to provide a health buffer for weaker ranged classes. Frequently maneuvering or other tactics are used by the tank to make themselves the most tempting or highest-priority target of enemy attacks, thereby diverting enemy attacks away from allies. Many basic strategies in games such as StarCraft and Warcraft III revolve around learning to micro-manage units so they attack tanks first so that the tanks do not continually attack units.
In group play found in many role-playing games, the role of the tank is to protect players that are low-armor or low-health classes. The role of a tank is typically to survive an oncoming attack, and then ensure that they are the target of the incoming attack. It then falls upon the healer (in large scale play, often specifically assigned to the role, with spells specializing with high healing output over one or two targets) to restore the tank's health so he does not die and allow him or her to take the next attack.
In MMOs, there is typically a mechanic that tanks rely on known as enmity, "aggro", or "threat", which is generated from damage and taunts. This makes monsters attack the tank. However, when fighting other players tanks will attempt to interrupt spell casters and apply debuffs, making them a high priority target for damage (as they are nullifying or mitigating the potential of the opposing team). Tanks are typically central to group play, and a large amount of responsibility is placed on the tank. Often a tank's death will cause the monsters to overrun the party as they cannot cope with the magnitude of incoming damage.
The term originally came in use with players of MUDs (Multi-User Dungeons), the text based predecessors of MMORPGs, and was used as early as 1994 on Usenet to describe the warrior class on DikuMUDs which had high hit points and the rescue skill, which allowed transferring one attacking mob from another player to the rescuing character.
In most games that feature a clear-cut "tank" class or character, there are three factors that contribute to a tank's survivability. The first is a large amount of health for absorbing damage that would normally go to lower health classes. The second is damage mitigation, the ability to lessen the damage attacks do in the first place. This is often accomplished through a high armor or defense stat mechanic. Finally, there is the ability to avoid attacks altogether. Depending on the game and class, a tank may focus on any combination of these. Examples:
- World of Warcraft is designed more around effective HP to ease the strain on healers by providing a buffer for them while they cast healing spells. This is achieved by obtaining gear with stats related to HP and defense as to ensure they are not 'one shot' killed by the encounter, and then obtaining mitigation stats to reduce the overall damage taken. In The Burning Crusade not having 102.4% mitigation would cause bosses to use increased damage attacks on their target. Their 'threat' mechanic is typically boosted by statuses typically known as 'tankmodes' which increase the threat produced by each attack, however tanking gear typically has damage-increasing stats to assist with damage output. Reactive damage spells, like Retribution Aura or Holy Shield also contribute to threat produced, as they 'hit' the enemy when the tank is attacked. However, the Druid class has distinct style of tanking, which typically solely focuses health pool to resist damage.
- In Final Fantasy XI two commonly used tanking styles are nicknamed "Blood Tanks" and "Blink Tanks". A blood tank focuses purely on being able to take many hits, through either higher than usual HP pools, heavy defense ratings, or both. A blink tank, on the other hand, focuses on higher than usual evasiveness and/or misdirection effects such as "shadow images", so as to prevent the damage from landing on the player in the first place. Depending on the type of fight you are going into, one of these two types of tanks is typically more suitable than the other. For example, against slower, less accurate enemies, a blink tank is ideal. In the proper setup, a blink tank will take hardly any damage at all, thus allowing party member resources that would otherwise be focused on the survival of the tank to be directed elsewhere, such as increasing DPS or enfeebling the enemy. Conversely, against faster, more accurate enemies, a blood tank is typically the tank of choice. A blink tank typically can not withstand nearly the damage a blood tank can, so in cases where damage is unavoidable, a blood tank usually fares much better. In Final Fantasy XI, blood tanks are of the Paladin and (to a lesser extent) Warrior classes, and blink tanks are of the Ninja and (to a lesser extent) Thief classes, although recent changes to the overall level cap and abilities of certain classes have expanded what classes can tank in certain specialized situations.
- In Eve online, tanking can be achieved by all pilots who fly attack ships. Three main types of tanking are shield, armor, and hull. Each type can be maximized through a combination of bonuses from skillbook training, implants, ship modules, repair drone support. Due to limited ship module capacity, a tank must focus installed modules in one area (shields, armor, or hull) to maximize defense yet leave room for offensive modules. For example, a shield tank ship will have greater hit points in shields and low hit points in armor and hull. Speed tanking is an action of moving so fast that any damage dealt to the fast-moving tank is minimized or negligible/unhittable. Spider tanking is a combined effort by defending ships repairing each other during combat. Spider tanks are able to withstand targets that deal very high damage. Logistics ships, or "logies", keep tanks alive in combat by "transferring" capacitor energy for shield tanks, armor repair "energy" for armor tanks, and hull repair "energy" for hull tanks. Typical types of tanking decrease the amount of damage taken or the effective health pool, and use repair modules (which resemble healing classes in RPGs) to repair incoming damage.
- In Warhammer Online each race has their own tank class. Three races on each side give each side 3 tanks to choose from. The classes are mirrored, but the tanks are generally divided into a Heavy Tank (Ironbreakers and Black Orcs who focus on sheer mitigation and blocking combined with large health pools which makes them superior at 1 on 1 tanking) a Reflective Tank (Blackguards and Swordmasters who have a variety of counterattacks to deal high damage) and AoE tanks (Knights and Chosens who are able to use their auras and AoE attacks to tank lots of enemies at once). In Warhammer, tanks have the ability to Guard another player and channel some of the threat that the player deals into their own threatpool. In PvP, tanks are able to storm the frontline and body block, or hold the line to reduce incoming damage. They can also challenge and taunt enemies off their allies.
- In Sins of a Solar Empire, the Radiance Battleship has an ability called Animosity, which causes it to take all incoming damage. This can allow the Rapture Battlecruiser to deploy a reactive damage spell. While this does make incoming damage easier to focus on and repair, tanking as a form of damage dealer is sometimes useful in solo play in MMOs and if the mechanics allow, a valid tactic.
- In Lord of the Rings Online, the Warden class is capable of an additional type of tanking—self-healing. The Warden has high hit points, but lacks heavy armour and does not have the same damage mitigation capabilities of a Guardian (the traditionally styled tanking class of LotRO). To compensate for the lack of heavy armour and weaker mitigations, Wardens are able to extensively heal themselves in combat, though not generally to the point where they do not require a healer. These self-heals are Heals over Time (HoT), which means that Wardens are still vulnerable to burst damage. The Champion class is also somewhat viable as an "off tank" in certain situations, but this requires one to gear specifically for this role, and is pretty rare as the trade off in Champion's high DPS abilities generally preclude them from being utilized in this role.
- In Allods Online tanks are Paladins and Champions (Warriors). While both tanks are quite effective at any given tanking needs, one specialises in some areas more than the other. Paladin focuses on single-target tanking, and dealing considerable damage in the process of tanking. Paladins rely on specific 'barier' feature and skill of the paladin archetype to mitigate large amounts of damage with ease vs single target. And having strong Strength values, since it affects and empowers paladin barrier skills and abilities altogether. Warrior focuses in multi-target tanking, and controlling the enemy, mostly trough the use of stunlocks. Warriors rely on having solid Stamina/Vitality/Hit points, and strong Agility which reduces magic damage taken,and affects dodge, block, and parry chances, which greatly reduces physical/melee damages. Apart from being able to tank effectively, both of the tanks have various skills which help protect and defend, or otherwise support their group members.
See also 
- Healer (gaming) is another common archetype focused on restoring the health of one's allies.
- Spell-caster (gaming) is another common archetype focused on dealing damage, but is relatively weak in all other regards.
- DPS is another common archetype also focused on dealing damage.
- Towers, J. Tarin; Badertscher, Ken; Cunningham, Wayne; Buskirk, Laura (1996). Yahoo! Wild Web Rides. IDG Books Worldwide Inc. p. 152. ISBN 0-7645-7003-X. "Tanks: Leading the ChargeNo, we're not talking about those huge army vehicles. Well, yeah, some MUDs do have that kind of tank in them, but that's not what we're referring to. A tank in a typical fantasy MUD is the character who, alone or in a group, is always the first to attack a monster. A mob will direct its attacks at the first person that hits it, so in a group the tank is generally some character with enough hit points to withstand this punishment. Meanwhile the others hack safely away at the adversary — at least until the tank is killed and somebody else becomes the lucky target. Some MUDs now have monsters that can switch their attacks to other characters in the group, so the tank approach doesn't work as well with them. If you're a newbie and are asked to join a group, it's important that you understand this concept. Listen to the leader and only attack after she says, or you may end up tanking something that will toast your hide in seconds."
- WoW Insider: Tank Talk. Accessed 17 August 2010. http://www.wow.com/2008/06/26/tank-talk-great-power-and-great-responsibility/
- David A. Wagner (07-08-1994). "tintin++ suggestions".
- Richard Hudson (30-11-1994). "tintin++".
- Righteous Fury – Spell – World of Warcraft. Accessed 17 August 2010. http://www.wowhead.com/spell=25780
- Reply to "strategies for the advent?" by Annatar11. Accessed 17 August 2010. http://forums.sinsofasolarempire.com/175645/get;1584649