Tanking is the process of putting specially designed characters(Tank Build) into harms way, which distract high-impact monsters(Bosses/Uniques/Traps) from dealing damage to Damage-Dealing Players(Ranged/Melee Attackers).

Typically the Tank build player is using equipment with high bonuses to defense, regen and life, with character class that has defensive passive skills/bonuses/buffs, without major investment in offensive skills. The only objective for tanker is to be targeted by the monster:survival is mostly ensure by other players healing and buffs/passives.

Major Battles in RPG setting require the design to acknowledge the player tactics.

The party combat is centered on two aspects of battle:
1.Not allowing the Tanking player to die(with heal/aura/buffs)
2.Not allowing the monsters to shift their focus from tanking player(s) toward ranged players. Shifting focus to another Tanker is desirable if one life/energy are nearly depleted.

To increase difficulty, many RPGs involve anti-tanking tactics applied to major monsters(bosses/uniques).
Some types of RPG countermeasures to tanking involve:
1.Monster switching focus randomly.
2.Teleporting/jumping abilities to reach hit-and-run attackers.
3.Boss monster spawning minions that pick off different targets.
4.Life leech that steals life from tanker player: i.e. making tanking benefit the monster.
5. Short-range damage aura:prevents melee tankers from close combat.(also prevents most melee combat)
6.Game rebalancing that makes defense-oriented builds less effective: this also ruins defense for all players less equipped/skilled than Tank Build.
7. Time-based bonuses to boss monsters: ensures that slow tanking processes will not slowly destroy the monster, but instead add some bonus to him that makes the battle more challenging: e.g. full regen or additional aura/curse/buff.