A theory on threat in Guild Wars 2

This is all based on my own personal experience and not any private knowledge of the mechanics of the game or other research.

What is threat, and why do I care?

Threat is the measure of the amount of anger a mob has towards a player.  It determines who the mob is targeting at any given time.  The person with the highest threat is attacked.  When you're questing on your own and happen to be in the same area fighting the same mob as someone else, threat is not a big deal.  If it hits you, or it hits me, the fight is usually over so fast that it's irrelevant.  However, in a five-man dungeon it makes a much bigger difference.

What determines threat?

The primary factor that goes into threat is damage dealt to the mob.  More damage dealt is more threat.  However, there are probably many other factors that go into it.  Here's a non-exhaustive list:

• Non-damaging conditions applied (blindness, stun, cripple, etc.)
• Actions being performed (reviving someone seems to temporarily spike the threat of the reviver)
• Distance between the player and the mob (more distance = less threat), adjusted for movement-impairing conditions
• Healing done
• Boons applied
• Trait/skills/professions?  I wouldn't be surprised to know that Guardians and Warriors have threat multipliers.
• NPC type (pets seem to have huge threat multipliers)

Ok, this is a lot of stuff.  What's a simple example?

Let's say you and your friend are attacking a wolf.  You both hit it simultaneously, and are equally distant from it.  You deal 125 damage.  Your friend deals 100 damage.  The wolf attacks you (this is called drawing "aggro"), because you have more threat.

That seems simple and obvious.  What about something more complicated?

Let's pretend that one point of damage dealt = one "point" of threat.  Applying a condition, like blindness, generates 50 "points" of threat.

Same as the previous example with your friend and the wolf.  You deal 125 damage.  Your friend deals 100 damage, but ALSO applies blindness with that same attack.  The wolf attacks your friend, because your friend has racked up 150 points of threat (100 damage + 50 blindness) to your 125.

Wait, but sometimes I out-damage people I'm with and I still don't get aggro?

Mobs have a minimum threat difference before they will switch targets.  Let's use the previous example.  Your friend has 150 points worth of threat (and thus has aggro) and you have only 100.  Let's say you hit the wolf with a skill that does 60 points of damage, putting your threat at 160.  The wolf does not immediately turn and attack you because you have not gone past the minimum difference in threat.  For the sake of example, let's say that difference is 20%.  Until you reach 180 points of threat (150 * 1.2) the wolf will not attack you.  (The reason behind this is to make the game more difficult- if the wolf changed targets immediately on one threat passing another it would waste a lot of time walking between both of you, plus you could "ping pong" it back and forth in the middle if you were good enough)

Do mobs remember threat?

Yes, mobs remember threat of all targets until they reset. This is called their "threat table".  The current threat table for the wolf from the previous example looks like this:

Friend: 150 (has aggro)
You: 160

What other factors affect points of threat?

Not all sources of threat are valued the same.  For example, you generally heal way less than you damage, so points of healing likely have a threat multiplier.  For the sake of example, let's double it (2x).

Starting from the previous example, you currently have more threat than your friend, but don't have aggro because you haven't passed the threshold yet.  You now heal your friend (who is being mauled) for 50 points of health.  With the multiplier, that is 100 points of threat.  The threat table now looks like this:

You: 260 (has aggro)
Friend: 150

That 50 points of healing generated more than enough threat to put you over the 180 threshold amount, and now you're being mauled instead of your friend.


Before you die, you summon a pet to help out.  Pets seem to have huge threat multipliers so that they are targeted more often.  Let's say that the multiplier is five times (5x) for this example.  You summon your pet and they deal 75 damage after spawning.  This is the threat table now:

Pet: 375 (has aggro)
You: 260
Friend: 150

The pet picked up aggro because it has more threat than you AND is over the threat threshold (260 * 1.2 = 312).  You and your friend are free to damage the mob risk-free as long as you don't pass the next threshold (375 * 1.2 = 450).

Where does movement-impairing skills play into this?

Impairing the movement of a mob, especially a melee one, likely does something akin to increasing the threat threshold as long as the current target is within attacking distance.

Again starting from the previous example, pretend you now deal 200 damage to the wolf.  This is the wolf's new threat table:

You: 460 (has aggro)

Pet: 375
Friend: 150

You exceeded your pet's threat and the threshold, so you are attacked.  Now let's change the scenario slightly.  Pretend your 200 damage attack crippled the wolf.  This has the effect of increasing it's threat threshold by 20% as long as its current target is in attacking range (again, making up numbers here).  Let's also say that crippling generates 50 points of threat.  This is the new threat table:





Pet: 375 (has aggro)
You: 510 (260 + 200 from damage, + 50 from cripple threat)
Friend: 150


Why does your pet still have aggro?  The cripple increases the pet's new threat threshold to 525 (375 * 1.2 [default threshold] * 1.2 [cripple bonus]).  Until you pass 525 you won't get attacked by the wolf.

(Quick note: the above omits an important thing I've noted.  I believe pets spawn with a large amount of threat- I wouldn't be surprised if they spawn with equal to or greater than the threat of the current highest target.)

What about being downed?

Being downed most likely reduces your threat.  For the sake of example, let's say it halves it.

You and your friend are fighting the wolf, with this threat table:

You: 150 (has aggro)
Friend: 100

The wolf "downs" you.  This halves your threat, and now the threat table looks like this:


Friend: 100 (has aggro)
You: 75 (150 / 2)

This gives you a chance to recover while your friend fights the wolf.


However, note that you can easily build enough threat that the wolf will not leave you alone even if you are downed.  If you had done 250 points worth of damage, you would still have 125 after being downed, and thus will still be attacked until you are dead or your friend dishes out more damage to the wolf to cross the threat threshold.

So how does this affect dungeon runs?

The end result of all this is that the people who are doing the most "stuff" and are closest to the enemy are most likely to get attacked.  This seems obvious, but it is important to consciously realize that this is the case.  This means that if you are being attacked and are likely to die, you should stop damaging you enemies (unless it would kill them) and try to run from them, preferably in the direction of one of your healthier allies.  Additionally, movement-impairing conditions will help you not only build distance but encourage the enemies to change targets.  Conversely, you should unload all of your skills on a target who is chasing one of your nearly dead allies so that YOU pick up the aggro instead of them, giving them a chance to heal.


Furthermore, there are interesting lessons to be learned here.  For example, try not to generate so much threat that a mob will keep attacking you even after you are downed; it makes it very hard to revive you and is easily avoidable with disciplined play.

My suspicion is that this passing and management of threat will be a critical part of elite play in dungeons, especially in end game content.

Additional notes:

People who have come from WoW will definitely notice the similarities between my theory and WoW threat.  The underlying system is the same, for sure.  My only additions are mentioning the importance of positioning, cripples, revives, etc.

Also, and I think the devs have said this and a lot of people have noticed already, a lot of mobs have personalized AI that messes with the standard threat system.  For example, attacking people who are at low health, prioritizing melees over anything else, etc.  Additionally I've noticed that there seems to be scripted AI for some story encounters (and even some quests) where mobs will attack certain targets and ignore any other threat you may generate.

Overall, I think we can all agree that the threat system is much more complex than it is in WoW, and certainly leads to a higher skill ceiling because of this.