Aggro, or aggression, is how the infected in an area behave in response to a survivor. Aggro is one of the most commonly heard terms in Dead Frontier. It refers to the amount of attention the zombies in the Inner City give you.

Overview

Across the community, uses of the term "aggro" can be roughly categorized into 3 types:

Hearing Range Aggro

All firearms and Chainsaws also generate "noise" that will attract zombie on-screen, causing them to progress 1 step in the zombie behavior chart (Calm -> Disturbed -> Enraged). The chance of creating "noise" corresponds to how "loud" the weapons are: Melee Weapons are completely silent, Pistols/Rifles infrequently generate "noise", Chainsaws/Machine Guns/Flamethrower have a higher chance, and Shotguns/Grenade Launchers are guaranteed (100% chance) to do so.

Event Aggro

Event aggro refers to the state of constant aggro in certain block. While event aggro is on, it is completely impossible to "kill off" the aggro and return to a quiet state. Event aggro only exists outdoors; any building inside the block with event aggro is safe.

• All Bosses/Bandits instances are accompanied by event aggro, whose strength depends on the instance's threat level. Level 1 instances have almost no aggro to speak up, while level 4+ instances have heavy aggro.
• Certain Missions will also be met with event aggro in the respective mission block, until their objectives are completed.
• Quick Reaction Force events and Outpost Attacks enforce event aggro around the blocks for their duration.
• In the Wastelands, all types of aggro spikes (natural, artificial, Canary screams) are automatically converted to event aggro, with the horde counter periodically refreshing to 150 if you try to kill it off. This lasts until you log out, or escape to the topmost 2 rows of blocks in the Wastelands.

Event aggro overrides aggro spikes; if you get an aggro spike, entering a block with event aggro will instantly kill off that aggro spike.

Aggro Spikes/Hordes

Aggro spikes is a phenomenon in which the game switches to high aggro state for a short amount of time. Unlike event aggro, aggro spikes can actually be fought back, with enough perseverance and effort from the player.

• While event aggro is tied to certain blocks and thus will try to harm all players equally, aggro spikes are tied to players and zombies spawned by it will prioritize the targeted player over others. Thus, players nearing one that is targeted by an Aggro Spike can choose to flee without fear of being "infected" by the aggro spike itself.
• Upon an aggro spike, a counter of up to 150 zombies (depending on zone) is displayed, which can be depleted by killing zombies. Additionally, fleeing to another block will deplete the counter by 30, as long as that block has not been visited recently (in ~20-30s). The second method does not work in high level zones, such as the South Eastern Zone.
• Once it is depleted, the aggro spike is defeated; the game then ceases to spawn any new zombie in the block, and prevent any new aggro spike from being started for a short moment afterwards.
• Sirens/Canaries also share this counter, and would add 3 zombies to the counter in addition to alerting all nearby zombies upon screaming.
• Two types of aggro spikes exist:
  • Natural aggro spikes are those that are generated randomly as you venture in the Inner City, regardless of which weapon you use. There are no guarantee on when or where it may appear - an aggro spike may randomly happen even if you just entered for a few minute, or might not happen even after you have played for an hour. The chance of its occurence is affected by Weather condition, as well as the player's Stealth stat.
  • Artificial aggro spike are those that are generated from excessive usage of Chainsaws, Sub-Machine Guns, Assault Rifles, Heavy Machine Guns, Grenade Launchers and Flamethrowers. Using these weapons sparingly with pauses in between will minimize the chance of artificial hordes.

Effects

Hearing Range Aggro

Each attack from a firearm or a Chainsaw has a small chance to generate hearing range aggro, causing all zombies on screen to move up one stage in the zombie behavior state chart, which goes as follows:

Calm (endless wandering) -> Disturbed (slow chase) -> Enraged (quick sprint)

• For example, if there's a zombie that is slowing you in the Disturbed state and another zombie wandering in the Calm state and the roll for hearing range aggro succeeds, the first one shifts into Enrage mode and the second one shifts into Disturbed state. Another successful roll does nothing to the first one, but also causes the second one to switch into Enraged state.

Event Aggro/Aggro Spike

Event aggro and aggro spike will rapidly attempt to spawn zombies in the area around the afflicted player. Foes spawned in this fashion are always of the Enraged state, and will start charging forward as soon as possible.

• When indoors, aggro spike favors spawning zombies at building entrances and stairs. Thus, if you stand near those locations, zombies will primarily spawn from those entrances' direction instead of from all sides.

What Should I Do?

Aggro Spike

Aggro spike during a loot run or a commute is undesirable, as it restricts your ability to run around or search bodies, cars, etc. Using loud weapons, such as Shotguns and Grenade Launchers, will cause aggro and should be avoided unless absolutely necessary. Excessive use of these weapon that leads to artificial aggro spikes is met by universal disgust from other players - if you want aggro for EXP, go to a boss block instead.

When aggro spike (natural or artificial) inevitably happens however, all bets are off and use of loud weapons for survival becomes the norm. There are 3 ways to survive an aggro spike:

• Run Away: Fleeing across city blocks can deplete the horde counter and eventually end the spike. Keep in mind that you need fresh blocks, so rapidly alternating between 2 nearby blocks would not work. Additionally, later zones such as the SEZ do not allow this tactic at all.
• Survive Indoors: Take advantage of Grenade Launchers' indirect fire capability, and camp at a length of wall next to a door or stairs entrance. Most zombies will be forced to spawn from these entrances, and get trapped by the wall for an easy kill. A disadvantage to this method is that it is rather slow, as zombie spawn rate is reduced indoors.
• Take the Fight Outside: Bring your best crowd control weapon, exit the building if you are in one, and fight the zombies in an open location. While dangerous, this is the fastest way to clear an aggro spike as spawn rate is not throttled outdoors.

Event Aggro

Event aggro is a constant threat in boss/bandit blocks, QRF blocks and the Wastelands. Your reaction will thus depend on what you want to do there:

• Boss/Bandit Hunting Event aggro serves as the primary complicator in these situations: Zombie reinforcements are capable of soaking up hits for the bosses, and complicating your effort to dodge their attacks. Crowd control weapons are thus heavily recommended to clear your path to the boss, as quickly as possible.
  
  There are 2 ways to isolate the bosses from event aggro reinforcement: Find a length of wall/fence and let the zombies get trapped on the other side, or do laps around the block and let you plus the bosses outrun the aggro. For the first method, do not kill already trapped zombies, as the game will then attempt to spawn replacements that might end up on your side of the wall. For the second method, have high speed boost from Drugs/Implants, watch your sprint energy, and keep an eye on the Minimap (expand it if needed) for any possible obstruction.
  
  Event aggro is also the reason Multiplayer bossing is recommended, especially for lower level players. Other players can provide supporting fire to clear reinforcement zombies, and work together to DPS the bosses/bandits.

• Level Grinding: Event aggro blocks provide a reliable supply of zombies, making them ideal places to gain EXP.
  
  Grinding can be done by slowly circling around a block or camping in an open space, such as the 4 corners of a building block. The first method reduces the chance of getting surrounded, while the second requires less memory capacity. It is imperative to avoid grinding in Multiplayer as zombies might get distracted by passerby's, endangering them while also reducing your EXP rate.