Guild Wars 2

This has to do with aggression table of mobs. I play many classes and have been completely confused by the agro table. For instance a missile turret does tons of damage yet the healing turret generates more aggression with exception of thumper turret? My Flesh Golem does both healing and significantly more damage than the Blood golem and yet it generates more aggression with exception of Bone Fiend? There seems to be no rhyme or reason to the what generates what aggression even the gw2wiki doesn’t make sense given the aggression of mobs seems to change on a whim. For instance my ranger can use a long bow and never pull aggression yet same build and wielding a staff suddenly my pet can’t hold a mob?

Egrimm Van Horstmann.7921:

There seems to be no rhyme or reason to the what generates what aggression

For most of the content, this is the correct answer, or at least, it feels like it. Apparently distance and the type of mob plays into account as well. There are a select few bosses in raids that have unique aggro mechanics though. For example, a specific attack that targets the furthest player from the boss, or an enemy that straight up targets the person with the highest toughness.

Egrimm Van Horstmann.7921:

There seems to be no rhyme or reason to the what generates what aggression

You’re assuming that there’s one rhyme and one reason, as there might be in other games. It depends on the mob and the situation. It could be any of the follow or even several:

• Highest toughness: some raid bosses use this and this alone.
• Sickest: some mobs target their foe with the least health.
• Weakest: the one that seems glassier (possibly a combination of health + toughness)
• Most damage: whoever is hurting them the most gets their attention.
• First to hit them or last to hit them.
• The one causing the most annoyance to the boss, that is, “adds” will sometimes go after the boss’ aggro target or sometimes an alternative target to free up the boss.

Low level mobs will do dumber things, like stay on the pet all the time and challenging content bosses will (often) focus attention on more sensible targets. That’s exactly what good AI should do — keep us guessing, so it’s not so easy to control them.

In practice, of course, the AI isn’t all that intelligent and it’s always artificial, so it can exhibit quirky & unexpected behavior.

Still, if you look for rhyme & reason with specific foes, you’ll see patterns emerge.

tl;dr It’s not any one thing; it’s a variety.

Short answer : Its random.

Long answer: The mobs have an internal AI which keeps track of many things, but instead of following a script like most other games its a bunch of weighted conditions based upon the situation at hand, and the specific type of enemy.

Basically what this means is, the mob will change targets depending on what it feels is the best target to attack in that situation, after evaluation. A good example is the revive ability, which will make almost any mob aggro you immediately because of the supportive role of it; but afterwards they will probaly go back to prefering the highest damager, in order to better protect themself.

But the general rule of thumb is, the first player to get the mob’s attention will stay aggroed until it has reason to change aggro, and things like, that player getting downed, or moving away, or reducing DPS, or other players using support skills and reviving, will change this aggro to them for either short or long periods of time, again entirely dependant on what is happening in the encounter.

The biggest difference between mobs is that each of them is tuned, to varying initial settings, such as prefering to attack tanks, or prefering to attack DPS, etc. Raids especially have bosses that have had their aggro tuned for classic Holy Trinity style groups, while dungeon bosses will usually expect players to all be DPS.

The later is mostly a relic of pre-HoT using a very (extremely) basic AI, which was rewritten entirely for the expansion release.

There are so many variables the devs can use to determine how aggro is directed. I got the feeling that the Legendary Bandit Avenger knows I’m playing a thief and attacks me as soon as I get as close as 900 range after firing only a few bullets at him. Or maybe he knows that I killed X bandits or whatever. The possibilities are endless. They could even change how a mob aggroes with every respawn, by using the random generator to select from several options.

I would love to have a glimpse on the code that’s used for aggro (or not, depending on the documentation standards Anet uses).

I know the champs in Orr will target rare armor, high toughness combined with high health.

When I first started out my ranger had rare knights armor and I was traited for high health also. All I had to do to take aggro from a group of people fighting an Orr champ was to show up and plink him once with my shortbow. If I died and came back I didn’t even have to attack to regain aggro. As soon as I got back in range he’d stop fighting the melee player and run towards me.

That quickly convinced me to upgrade my armor and change my stats.