SWTOR Tank School: Aggro/Threat

Chapter 2: Aggro/Threat

This is a generally misunderstood subject, and it's not surprising since it's not really documented anywhere . . . which is one of the primary reasons for creating this series of articles.

What is Aggro?
Aggro is simply the system by which the game decides whom a PvE enemy will attack. As a Tank, you want those enemies to attack YOU, so it's important to know how it works so that you can most effectively manipulate it.

What is Threat?
Threat is a just synonym for Aggro. You will see both terms used here, in the context in which they are typically used. They are mostly interchangeable, and I'll be deliberately using both so you get accustomed to hearing both being used.

How does Aggro work?
In its simplest form, when multiple players attack an enemy, that enemy will choose to attack the individual who has done the most damage to it. This player "has Aggro" on that enemy. If some other player suddenly does more damage than the one who has Aggro, then the enemy will switch targets to the new player with the highest damage. This player has "stolen", "pulled", or "ripped" Threat from the other player.

Every enemy maintains a hidden "Aggro Table" and tracks how much total damage has been done to it by each player. The amount of damage done by a given player is his or her Threat Level. The player at the top of that table is (almost) always the one who gets attacked.

But of course, it's not that simple.

When healers heal a player who is attacking an enemy, the enemy considers the amount of healing done to be just like damage done to it. In this way, healers also threaten an enemy and the amount of their healing gets added to the Aggro Table just like damage. Healers can even steal aggro if they do enough healing that it exceeds the amount of damage done by any of the DPS characters and they end up on the top of the list.

So your job as a Tank is to "hold aggro" by putting yourself at the top of that Aggro Table and staying there.

Thankfully, the Aggro Table isn't just a table of damage done, but actually a table of Threat Level, which is very similar, but not quite the same (as you've already seen for healers).

How do I know what my (or someone else's) Threat Level is?
The only way to do this is to turn on Combat Logging in your Preferences, and use a tool that parses the log files to show you those numbers.

A number of parsers have been developed (and abandoned) over time, but at the time of this writing the most commonly used program is StarParse.  There is also a newer program with some unique features called ORBS.

How do I get and hold Aggro?
As a Tank, you will not be able to do more damage than the DPS characters in your group. (If you can, that's a whole other problem.) But thankfully, it's actually Threat Level that counts, and what you CAN do is generate more Threat than the DPS characters (and healers) in the following ways:

1) Using your "tank stance" to boost the threat of all your attacks
2) Using attacks that "generate a high amount of threat"
3) Using Taunts
4) Using your Guard

What's a "Tank Stance"?
Earlier in the game's lifetime, certain advanced classes had a way of selecting from 2-3 special buffs that stay with you unless you deliberately change it or remove it called a "Stance".  In later versions, the stance became automatically selected based on which spec you choose, and the ability to change it was taken away.  The visible "buff" that appeared on your character's buff bar was also taken away.

For the sake of trivia, here's the list of the applicable stances.  They do still exist, but they're now automatically-chosen, hidden and you can't change them.

If you could read the descriptions of each of these abilities, all six include wording that says threat generation is increased by 150%. This means that the amount of threat you generate is TWO AND A HALF TIMES the actual amount of damage you do on ordinary attacks. So as long as you can come close to doing 40% of the damage the highest DPS does, you can keep the enemy attacking you and only you. Remember: it's the amount of THREAT generated that determines which player an enemy will attack, not damage.

What are "High-Threat" Attacks?
Every tank-capable advanced class has a few special attacks that generate more threat than the amount of damage they do. This can be inherent to the attack (e.g. Slow Time), or a result of a skill tree selection (e.g. Guardian Slash?). So to maximize the generation of threat, you will want to use these attacks as often as you possibly can.

What happens when I Taunt?
This is an often-misunderstood concept, typically because people who have played other MMO's incorrectly assume that a Taunt in SWTOR does the same thing that it did in other games. It may or may not.

A Taunt does 2 things to its target:
1) It forces the target to ignore its Threat Table for six seconds, and instead focus on the taunting tank exclusively (unless another tank does a Taunt during that period).  
2) It takes the current highest Threat Level from its table, increases that number by 10% or 30%, and assigns this new, increased value to the taunting tank.  The increase depends on your distance from the target: If you are within 10m of your target, the increase is 10%.  If you are farther away, the increase is 30%.

(NOTE: In PvP the effect of a Taunt is completely different since other players are free to choose their own targets at will. We will not discuss that here.)

Knowing this, you can leverage the behavior of a Taunt to your advantage in the following ways:

• In a situation where it is momentarily critical that a DPS not pull aggro off the tank (e.g. Kiting the Sandstorm Boss to a Canister in the Czerka Meltdown flashpoint), it can be prevented reliably with a Taunt, leveraging the six-second exclusivity it gives you.
• You should almost never start a battle with a Taunt. Yes, it gives you six seconds, but after those six seconds are up, you are very likely to lose aggro. Why? Because you started out with a Threat Level of ZERO, and increasing it by 30% is still ZERO. You've wasted an opportunity to increase your threat level, and won't be able to use it again for another 15-ish seconds.
• You can Taunt even when YOU ALREADY HAVE aggro on an enemy. This takes your current Threat Level and increases it by 10% / 30%, then reassigns that increased value right back to you.
• You should almost never taunt an enemy whose current target is another enemy (or, more generally, someone who is NOT you or one of your allies). Why? The "other" target is very likely to have a threat level of ZERO, especially if the change of target is due to a fight mechanic of some sort (e.g. when Heirad casts Surging Chain on Ciphas in the 2nd boss fight of Terror from Beyond).  In those cases, you will be taking that ZERO value (along with the 10%/30% boost which is still zero) and reassigning that value to you, overwriting whatever your previous (higher) value was.
• Two tanks working together can increase Threat VERY quickly by "Taunt Swapping", and increasing the highest Threat Level twice--which ends up being a 69% increase for a single swap and a whopping 185% increase for doing two swaps.
• Some enemies will, as a normal part of their attack sequences, drop aggro on you and/or temporarily select a different target from you.  It is important to know when that happens and which is which so that you can promptly taunt the boss back to you, or wait for the current attack to finish and confirm that the boss's target switches back to you naturally.  (Often this second type of scenario exists to goad you into using your taunt at a bad time so that you don't have it available when you do need it shortly after.)

There are two schools of thought on how often to use Taunts, and both have validity in the right circumstances.

The first strategy is "Taunt on Cooldown", meaning to use the Taunt as often as possible, leveraging the exponential growth of your Threat Level from multiple taunts. This has the advantage of quickly building and maintaining a practically unassailable Threat Level on the tank, but carries the disadvantage that the the Taunt ability might not be available at a key moment when needed. Also, certain bosses can defeat this strategy by simply dropping Aggro as a part of their attack sequence.

The other is "Taunt When Needed", meaning to hold the Taunt in reserve until a DPS actually steals threat. This has the advantage of keeping the Taunt ability available for when needed, but carries the disadvantage that loss of Aggro probably will happen, and it can cause real problems if it happens at the wrong time or to the wrong player. It is also not even an available option if the Tank simply cannot generate high enough threat compared to the DPS players in the first place.

With experience, you'll learn to blend these strategies properly to the situation. With proper gearing, you'll be positioned so that "Taunt When Needed" is actually viable, even against very high-output DPS's.

What does Guard do?
Guard is a special persistent buff that you put on another friendly player. It has 2 effects:
1) It reduces the damage that player takes by 5%.
2) It reduces the Threat generated by that player by 25%.
(NOTE: There is a third effect specific to PvP, which we will not discuss here.)

Many players focus on the first effect, using Guard primarily to protect a healer by reducing damage.

But the second effect is much more dramatic, and more useful. By putting the Guard on your highest-output DPS ally, you significantly reduce the threat that player generates. In doing this, you no longer have to outpace that DPS in Threat generation--instead you only have to outpace the 2nd-highest DPS ally.

Note that this is extremely helpful, but not foolproof. It is entirely possible that a DPS, under the right circumstances, can exceed the damage YOU do by more than 270% or so, in which case that DPS will still steal aggro from you even with the Guard.

So, to review the essentials of threat:

• Doing damage (and healing) causes Threat to be generated.
• The enemies will attack the one with the highest Threat.
• The Tank, in tank stance, generates more than double the Threat of his own damage.
• Special High-Threat attacks do more than double Threat, and are excellent for starting battles.
• A Taunt takes the highest Threat level, increases that value by 10% or 30% (depending on distance), and assigns that value to the taunting tank; and it prevents the enemy from going to another target with a higher Threat level for the next 6 seconds.

Coming up:
In the next chapter, we'll discuss proper gear, and how to optimize a Tank build for maximum rock-solidness.