Tanking is the act of taking damage in order to protect other players from it. It generally means taking the heavier, main damage from an enemy, be it monster or another player, though it does not necessarily mean that the tank takes all the damage. For example, in addition to attacking the main target, Nex also uses a magic attack directed at every player near her, dealing damage to everyone fighting her. Tanking occurs mainly in fights with higher level bosses such as Vorago, Beastmaster Durzag and Yakamaru.
The tank is often a very important player in a team launching an assault on a boss monster, and if the tank fails to do their job adequately, the team is likely to fail. For example, in addition to all the special attacks depending on rotation, Vorago uses two normal attacks, a Melee attack against his main target and a magic attack against the player standing farthest from him. As such, players usually designate role of base tank to deal with Vorago's melee attacks and role of bomb tank to deal with the magic attacks. If the designated tank dies or performs their job poorly, the other team members become susceptible to attacks they're not prepared to deal with. Should one of the tanks to die with no designated back-up tank to quickly enough assume the position of the tank, the rest of the team will likely die from receiving the powerful attacks of Vorago.
Provoke makes the enemy target you instead of other players, making it useful for tanks to maintain the monster's aggression on them, thus protecting other players from higher damage.
Anticipation reduces damage taken by 10% for its duration and prevents stuns, making it a decent ability for slight damage reduction. At some situations, such as Nex's smoke phase, the stun immunity can prove to be extremely helpful in avoiding unnecessary damage while stunned.
Freedom clears any stuns or binds and gives further immunity of them for 6 seconds and also removes any current damage over time effects. At Beastmaster Durzag and Yakamaru, this ability can also be used to reduce enrage stacks the tank may have accumulated through the fight.
Resonance is an ability that makes next received attack heal you for the amount of damage it would have dealt otherwise, making it a great way to both heal and negate damage as a tank. For some attacks, such as the Twin Furies' Channelled Bomb, Resonance only negates the damage without healing.
Preparation makes every hit taken in 10 seconds from activation reduce the cooldown period of Resonance by 3 seconds, making it a great ability in situations where Resonance is frequently used.
Debilitate halves the damage received from its target. It is especially helpful in boss fights where a single enemy deals high amounts of damage, for example Araxxor. Its disadvantage is that it must successfully hit the target in order to take effect, making it less useful against targets with high defence.
Reflect halves the damage taken for 10 seconds and reflects the other half to the enemy. This can be helpful for both reducing taken damage while also helping to deal more damage yourself; however, it should be noted that most bosses are immune to reflect damage.
Revenge is an ability that allows you to deal higher damage depending on how many hits you receive in its duration. This can be very helpful in situations where wearing a shield constantly is required in order to make up for the lower damage output the shield causes.
Barricade blocks all damage for maximum of 10 seconds, the duration scaling with the tier of the shield. This can be a useful ability at boss fights where a lot of damage is received in a short period of time, but requiring both 100% Adrenaline and a shield to be worn limits its usefulness greatly.
Immortality reduces any received damage by 25% for 30 seconds, and revives you to 40% of your max HP should you die while it's active. It's not very useful as it requires 100% adrenaline, but can be used as a last resort ability if you know you're likely to die.
Despite the name, Tank armour is rarely preferred to use over Power armour while tanking. This is because the damage boost from using Power armour allows the boss to be killed faster, resulting in less damage taken overall comparable to wearing Tank armour. Only exception to this are Primeval, Tempest and Teralith armours that have set effects such as increased damage while wearing a shield and a chance to reset cooldowns of Defensive abilities, which together with their high defensive stats make them a viable option for tanking.
When tanking, Shields are often used as a switch when using a defensive ability that requires a shield is needed. As such, shields like Merciless, Vengeful and Malevolent kiteshield are most commonly used as they provide best results with abilities that scale with the level of the shield.
For consistent tanking with shield, Arcane, Elysian and Divine Spirit Shields can be used instead for their 30% damage reduction. However, it should be noted that using these shields drains Prayer points for each reduced hit, by an amount equal to 6% of the received damage.
When both tanking and being able to deal high damage is extremely important, Defenders can be used instead of shield. Defenders act as both a shield and an offhand weapon, with the drawback of only having stats of a shield and an offhand half of its tier. For example, a tier 90 Kalphite defender equals a tier 45 shield and offhand weapon. Defenders also boost accuracy by +3% and have a chance of blocking 50%-100% of a hit while increasing accuracy of your next hit by +20%.
There are few pieces of jewelry that can help to reduce received damage, making them potentially good choices for tanking.
Amulet of Souls is a very useful amulet for tanking as it allows Protection prayers to block 60% of received damage instead of the usual 50%, as well as boosting the healing from Soul Split while also having great offensive bonuses.
Superior leviathan ring has a 5% chance to block 50% of the damage of a received hit. It can be used if the damage reduction effect of is deemed necessary, but generally rings like Asylum surgeon's ring or Ring of death are even better choices due to their greater offensive bonuses.