Siren (Killing Floor 2)

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The Siren
The Siren

The Siren is an uncommon specimen in Killing Floor 2. It is classified as a medium enemy. Sirens appear as emaciated, skeletal females, lacking eyes and facial features. They have metallic harnesses bolted to their bodies, which serve as crude bulletproof vests. Most notably (and dangerously), they also have a sonic amplifier devices embedded in their throats that allow them to unleash bone-chilling screeches that damage and visually disorient players within range.

Base Statistics

Normal Hard Suicidal Hell on earth
Kill Reward 25 25 25 25
XP 11 15 15 15
Base Health (body) 230 230 230 230
Base Health (head) 155 155 155 155

For kill reward calculations read Dosh Mechanics.


Melee (base damage) 13
Melee (damage multipliers vs. doors) 3
Melee (damage multipliers vs. players) 1
Melee (range) 180
Scream (cooldown) 4s
Scream (damage type) Sonic
Scream (explosion damage) 15
Scream (explosion falloff exponent) 1 (linear)
Scream (explosion frequency) 0.5s
Scream (explosion radius) 600
Scream (explosion repeats for X, times) 4
Scream (maximum distance from player to start) 900
Scream (minimum distance from player to start) 130.38

Siren will not initiate a new scream if player get closer than 130 units.
Scream attack can be interrupted.
The base damage value further modified by the difficulty-specific multipliers.

XP Notes

  • Killing with weapons other than your current perk grants the XP to the perk that weapons belongs to.
  • Damaging with on-perk weapons and then finishing it off with an off-perk weapon divides the XP and grants it to both perks.
  • Assist kills grants full XP.


Sirens move slowly when docile, and sprint when enraged.

On higher difficulties, Sirens have a chance to enrage upon sighting the players, and have a chance to enrage when shot.

Movement speed is randomized within ± 10% range and further modified by a multiplier based on difficulty.

Walking speed (per difficulty) (180 - 220) x (0.9 / 0.95 / 0.95 / 0.95) x (1 / 1 / 1 / 1)
Running speed (per difficulty) (248 - 303) x (0.9 / 0.95 / 0.95 / 0.95) x (1 / 1 / 1 / 1)
Hidden speed 600
Sprint chance Normal - 0 / Hard - 0 / Suicidal - 0 / HOE - 0
Sprint chance (when damaged) Normal - 0 / Hard - 0 / Suicidal - 0.65 / HOE - 0.85

For comparison, by default a healthy player character with the minimal weight walks at speed of 383 units/s, and sprints at speed of 460 units/s.

Sprint Conditions

Should sprint if can sprint when damaged AND damaged (i.e. if sprint chance met its value) AND if distance to player laying between 6 and 12 meters (600 units < distance < 1200 units). Should sprint when frustrated. The sprint speed is equal to the walking speed.

Resistances and Weaknesses

Damage Resistance

Sirens have a wide range of resistances, and no weaknesses.

Piercing Slashing Bludgeon Toxic Fire Microwave Explosives Freeze Shells Bleeding EMP
Damage Multipler x0.5 x1 x1 x0.25 x0.5 x0.85 x0.85 x1 x1 x1 x1

Ballistic Resistance

Sirens have no ballistic weaponry resistances, but interestingly, have one special weakness to the Double-Barreled Shotgun.

Sub-machine Gun Assault Rifle Shotgun Handgun Rifle Shotgun - DBS
Damage Multiplier x1 x1 x1 x1 x1 x1.1


Sirens have 2 weak spots, which are the head and the neck. Sirens wear a metallic plating over their bodies, which reduces the damage when they are shot in the chest and hips, acting as a crude bullet-proof vest. Note that damaging them in the neck is not the same as damaging the head; Damaging the neck will subtract from the body health, not the head health.

Damage Multiplier
Head x1.1
Neck x1.1
Chest x0.5
Hips x0.5
All other x1

Incapacitation Resistance

Affliction: Stun Knockdown Stumble Gun hit Melee hit Snare
Torso vulnerability: x0.5 x1 x1 x0.9 x1 x1
Head vulnerability: x2 x1 x1 x0.9 x1 x1
Legs vulnerability: x0.5 x1 x1 x0.9 x1 x2
Arms vulnerability: x0.5 x1 x1 x0.9 x1 x1
Special zone vulnerability: x2 x1 x1 x0.9 x1 x1
- Incap cooldown 5s 1s 1s 0.2s 0s 5.5s
- Incap duration 1.5s --- --- --- --- 3s
- Dissipation rate -20/s -20/s -20/s -20/s -20/s -20/s
- Incap threshold 100 for all incaps. Siren's special zone is a neck.
Affliction: Poison Microwave Fire panic EMP Freeze Bleed
- Vulnerability x0.15 x3 x0.9 x2.5 x1 x1
- Incap cooldown 20.5s 6.5s 6s 5s 1.5s ---
- Incap duration 5s 4s 5s 5s 4.2s ---
- Dissipation rate -10/s -20/s -10/s -50/s -20/s -20/s
- Incap threshold 100 (EMP Disrupt - 25, Bleed - 65)
Knockdown (getup duration) 2s
Stun (time + wakeup duration) 1.5s + 1.33s, for PvP ZEDs - 2s + 1.33s
Freeze (time + thaw duration) 4.2s + 1.33s, for PvP ZEDs - 2s + 1.33s
Stumble (duration) Between (0.87-1.4)s
Parry (duration) Between (0.87-1)s


The Siren is a glass cannon. It is a slow-moving, area of effect damage ZED.

Upon spawning, it will walk towards the nearest player. Upon getting close to a target, they will begin to attack by screaming.

Siren screams deal massive damage which increases based on how close they are to the player.

Siren screams ignore armor.

Siren screams will stack with other Sirens and deal damage separately.

Siren screams visually distort the area around them and cause players' screens to shake violently depending on how close they are to players.

Siren screams destroy grenades and explosives (including C4 that has been placed on the ground), unless used by a Demolitionist with the Siren Resistance skill.

After screaming, the Siren has a short cooldown time before it can scream again.

If a player is standing right in melee range of a Siren, it will attempt to scratch or bite instead of scream, though sometimes it will scream regardless.

On Suicidal and Hell On Earth, Sirens do not gain any additional abilities.

Miscellaneous Information


Frustration delay Random (2.5-5)s
Disabled, when total AI remains cannot teleport
Cooldown cannot teleport
When hidden, can use after cannot teleport
When spawned, can use after cannot teleport


Penetration resistance 1
Parry resistance 1
AI pause, on gun / melee hit 0.2s

Various information:

  • Siren cannot teleport.
  • (PvP) Rally boost: forces AI Sirens to sprint, players do x1.2 more damage.
  • Damage to doors = 39.
  • ZED mass = 50.
  • Should sprint if can sprint when damaged AND damaged (i.e. if sprint chance met its value) AND if distance to player laying between 6 and 12 meters (600 units < distance < 1200 units). Should sprint when frustrated. The sprint speed is equal to the walking speed.
  • EMP effect (disrupt) prevents Siren's scream attack.
  • Scream attack considered as an explosion with the "Sonic" damage type.
  • Scream attack can be interrupted.
  • Each scream attack is a group of 4 sub-attacks performed in waves.
  • Each sub-attack creates an anti-projectile shield that lasts for 2.2 seconds.
  • Scream cooldown timer begin with the first wave of each scream attack.
  • Siren will not initiate a new scream if player get closer than 130.38 units.
  • Visual effect of scream attack - 6 seconds.
  • Scream attack completely ignore the armor and does damage to the actual health.

Extermination Tactics

The Siren is deceptively durable despite its lanky build and looks. This is largely due to the metallic harness that they wear over their bodies which absorb damage.
Sirens are extremely dangerous specimens and are capable of killing entire teams quickly when too many of them are left alive to scream in melee range.
Sirens move very slowly, and therefore should be taken care of from a distance long before they have a chance to scream.
The presence of Sirens also disables the use of explosives, which can prove deadly when a horde of ZEDs are traveling with Sirens in the pack, who can scream to prevent explosives from easily taking out a group of ZEDs.
Sirens can be easily killed by perks that use high powered ballistic weaponry from a distance. Namely, the Commando and the Sharpshooter, who both excel at killing Sirens from a long distance safely.
Support Specialist can take out Sirens relatively well at medium to close range, but they risk taking damage from screams. However, one shotgun blast to the head usually decapitates them instantly. Interestingly, the game encourages Support Specialists to get up close and personal with the Siren, especially with the Double Barreled Shotgun's increased damage multiplier, to kill them.
The Berserker has no choice but to tank the scream if they are engaging Sirens. However, one well-placed strong attack to the head usually kills them instantly as well, stopping the scream immediately. Berserkers can also wait for the cooldown between Screams to attack.
Demolitionist can exterminate Sirens the quickest with their powerful explosive weapons that do not require perfect aim. Once a Demolitionist acquires the Siren Resistance skill, they can quickly and reliably dispatch even groups of Sirens with their high powered explosive weapons. Before then, try to only shoot at Sirens in between their screams.
When faced with groups of Sirens, it is often wiser to clear a path and back off so you can kill the Sirens safely from a distance, rather than risk getting surrounded by Sirens in every direction. A wipe is almost guaranteed if there are multiple Sirens screaming at the same time among the team, as the damage done by multiple Sirens stack.