The Tank or Defensive role is one of the four roles available in DC Universe Online.This role generally focuses on keeping the group safe by attracting opponents and taking damage in place of other group members.

Earth, Fire, Ice, and Rage have the ability to change to the Tank Role.
The symbol that represents a tank is a Shield.

(In PVP, Tanks have a disadvantage against Healers but have an advantage over Quantum, Light, Mental and Gadget Controllers.)

It is the job of a tank to reduce the overall damage a group takes. A Tank should disable and taunt enemies whenever possible with area effect powers that knockdown, juggle or stun. Pulling enemies and gathering them in one large group will make this easier. Powerful attacks should be dodged by moving out of range or breaking line of sight.

Blocking is extremely effective if done right. It will reduce incoming damage by approximately 70%, interrupt most weapon combos by stunning the attacker and provide protection against most crowd control effects. A Tank should always block if overwhelmed and the healer(s) can't keep up with the damage or if a big attack is coming and can not be dodged. However, blocking too long may strain power generation and cause enemies to bypass the Tank as active powers are necessary to taunt opponents.

Health : The amount of damage a player can take in battle

Dominance : Dominance affects Control Effects, Self Healing and Shield Damage Prevention
Dominance is doubled for all Tank power sets in Tank role

Defense : Reduces incoming damage from non player opponents Restoration : Affects Self Healing and Shield Damage Prevention

Critical Healing Chance & Critical Healing Magnitude : Affects Self Healing for Fire and Rage Tanks

Earth Tanking

Earth Tanks gain Damage Absorption and may Transfer additional damage to a Pet.
Using a power in Tank role will grant 25% Damage Absorption and will increase Defense and Toughness by 1 point for every point of Dominance.
Aftershocks from Gemstone Shield, Jackhammer & Upheaval will further increase Damage Absorption.
Damage Shift transfers a portion of incoming damage to a summoned golem and Reinforce transfers incoming damage from a team member to the caster.

Fire Tanking

Fire Tanks gain Health and Healing received bonuses and may use multiple Self Heals to restore Health.
Using a power in Tank role will increase Health by 60% and any Healing received increases by 80%.
Fire Tanks also gain 2.2 additional Health for every point of Dominance.
Healing from Absorb Heat, Backdraft, Burning Determination, Wildfire, Burnout, Overheat, Fiery Weapon, Stoke Flames, Eternal Flame and Reignition scale with Dominance combined with Restoration.

Ice Tanking

Ice Tanks gain Defense and Toughness bonuses and may use multiple shields to prevent damage.
Using a power in Tank role will increase a character's Defense and Toughness by 90%. Winter Ward, Bitter Winds, Shatter Restraints and Ice Elemental prevent additional damage equal to Restoration combined with Dominance.
Healing from Hibernation and Ice Elemental scales with Dominance combined with Restoration.

Rage Tanking

Rage Tanks gain Health based on the number of enemies and may temporarily defer damage.
Using a power in Tank role increases Health by 0.6 points per point of Dominance for each nearby enemy.
Relentless Anger and Severe Punishment activate a Rage mode that defers damage into a Rage Crash.
Several Rage powers have mechanics that reduce or ignore the delayed Rage Crash damage.

WeaponsBrawling and Hand Blast should be the first Weapon trees to spec into as Health and Dominance are first tier skills. Health is also a first tier skill in One-Handed, Rifle, Shield and Two-Handed. Dominance is a first tier skill in Dual Wield and Staff. Defense is a first tier skill in Bow, Dual Pistols, Dual Wield, Martial Arts and Staff.

Movements
All movement modes share two general perks useful to tanks. The first of these skills is a targeted pull that allows the tank to pull enemies towards them - Low Pressure (Flight), Tornado Pull (Super Speed), and Grapple Line Attack (Acrobatics), out of which Grapple Line Attack is the only one that isn't an area effect. Getting one of these abilities may be helpful to a Fire tank as a targeted Pull as Backdraft only pulls in nearby opponents.

Iconic Powers
Iconic Powers will taunt and activate Tank role bonuses just as super powers found in the main trees.
Hard Light Shield: Damage Prevention = Restoration + Dominance
Self Heals if using the Empowered Channeling Hands Equipment Mod
Useful for a Fire Tank as there is no Shield in either Fire tree
Amazonium Deflection: Adds 5000 Defense; Knocks down & Stuns nearby opponents
Prevents Control Effects and Counters including Block Breakers
Sonic Cry: Stuns nearby opponents
Mesmerizing Lasso: Ranged single target Pull
Useful as a ranged single target pull for a Fire Tank as Backdraft is a short range area Pull
Pheromone Bloom: 35% Supercharge; Self Heal; Knocks down & Stuns nearby opponents
Useful as a Self Heal for an Earth Tank as Envelop prevents movement
Word of Power: 50% Supercharge; Self Heal; Knocks back nearby opponents
Provides power to self and group.

Passive Iconic Powers
A few Passive Iconic powers may be useful to Tanks if Power points are available:
Powerful Resistance: Adds 100 Health
Fire Tanks have a 60% Health bonus so this adds 160 Health after a power is used
Intimidating Gaze: Adds 25 Dominance;
Dominance doubles in Tank Role so this adds 50 Dominance
Dominance is added to Restoration for Self Heals
Dominance affects damage prevention Shields
Fire Tanks gain 2.2 points of Health for each point of Dominance so this adds 110 Health
Earth Tanks gain 1 point of Defense for each point of Dominance so this adds 50 Defense
Nanoweave Armor: Adds 50 Defense & 100 Toughness
Ice Tanks have a 90% Defense & Toughness bonus so this becomes 95 Defense & 190 Toughness

Earth
Damage Shift :increases resistance to control effects by 10%.
Unstoppable :provides temporary Control Effect Immunity to teammates.
Damage Shift :transfers 25% of incoming Damage to a summoned Golem.
Reinforce :transfers 30% of incoming Damage from a teammate to the caster.
Gemstone Shield :Damage Prevention = Restoration + Dominance
Jackhammer and Upheaval :increase Damage Absorption to 50% after an Aftershock.
The higher health Brick Golem will taunt opponents if the health of the caster falls below 40%.
The Crystal Golem has an ability to apply Control Effect Immunity to the caster.
Totem :heals any nearby Golem by a small amount and knocks down nearby enemies.
Earthen Grip :is useful as a long range single target pull.
Epicenter :pulls all nearby enemies toward the caster.
Stone :is a single target taunt that will override other Tank taunts

Fire
Enflame and Immolation :increase resistance to control effects by 10%.
Burning Determination and Burnout provide temporary Control Effect Immunity to teammates.
Absorb Heat, Backdraft and Fiery Weapon :will self heal when used on Burning enemies.
Dominance and Restoration increase Healing from Absorb Heat, Backdraft, Burning Determination, Burnout, Overheat, Eternal Flame, Fiery Weapon, Reignition, and Stoke Flames
Backdraft pulls all nearby enemies toward the caster.
Flashpoint & Enflame are Radial crowd control abilities.
Reignition is a 25% Supercharge that provides a self-heal and will apply Burning.
Eternal Flame is a 100% Supercharge that doubles health and self-heals after each hit
Fireball is a single target taunt that will override other Tank taunts

Ice
Cold Snap, Ice Bash and Reflection :provide a Chill effect.
Five consecutive Chill effects activates Ice Armor which provides the 90% Defense Tank bonus.
Cold Snap and Bitter Winds :increase resistance to control effects by 10%.
Bitter Winds, Shatter Restraints and Winter Ward :prevent damage based on Dominance and Restoration.
Shatter Restraints and Winter Ward :provide temporary Control Effect Immunity to teammates.
Reflection :prevents damage from the next three attacks and deflects some damage back to opponents.
Inescapable Storm :is a multi target ranged pull.
Ice Elemental :is a 50% Supercharge that triples Health & Defense and Self Heals.
Frost Snipe :is a single target taunt that will override other Tank taunts

Rage

Ferocity and Ire :provide temporary Control Effect Immunity to teammates
Eviscerating Chain :is a single target taunt and pull that will override other Tank taunts
Without Mercy :pulls all nearby enemies toward the caster
Ragebringer :is a multi target pull
Redirected Rage :is a damage prevention shield
Relentless Anger and Severe Punishment :activate a Rage mode that heals and defers damage into a Rage Crash
Bloodlust, Galling Eruption, Lacerate, Remorseless Recovery & Violence :reduce the damage from a Rage Crash
Dreadful Blast, Eviscerating Chain, Outrage, Plasma Retch & Revenge :can be used to ignore damage from a Rage Crash
Vindictive :is a supercharge that Self Heals and provides immunity to Rage Crash
Without Mercy, Rage Blast, Ragebringer, Remorseless Recovery, and Channel Hate :provide a Self Heal based on the damage dealt