KF2 Firebug Guide: Purge With Fire - Weapons, Perks, Playstyles

This is an early community guide to the Killing Floor 2 Firebug, written after the big content update. The author's summary: a solid damage-over-time and debuff class that survives by sprinting around and tapping fire patches, with low immediate damage as its real downside. See also the general Firebug perk page.

Pros and cons

Pros:

• Mobile fire damage over time lets you kite well or reach teammates.
• Burning confuses and panics zeds; for example, Clots cannot grab while panicking on fire.
• Strong damage support: over time you and the team take less damage and save ammo.
• Good flame weapons for close and long range.
• Large ammo pool and decent at saving cash.

Cons:

• Can be annoying to play solo.
• Anemic impact damage. The trench gun is the only source and is only okay; solo on high difficulty, Scrakes and Fleshpounds are a problem with perk weapons alone.
• No speed or health bonus, so survival depends on the player.
• Spamming fire burns through ammo quickly.
• Weapons are moderately heavy.

Weapons

Quick notes:

• You can lay down fire while sprinting, staying mobile while purging many zeds.
• The boss (Hans) takes less damage from fire but a little extra from the microwave; exact numbers unknown to the author.
• Headshots still deal extra damage with fire weapons.
• A hidden meter builds on zeds hit by Firebug weapons; when it maxes, zeds panic. A few good trench gun shots or a Molotov impact can stumble a Scrake.
• Tapping the DoT weapons bursts more damage because each tap uses 4 ammo (3 for the Microwave Gun).
• Aim low but still land both impact and ground damage.

Caulk n' Burn: 4 ammo per click, tap repeatedly for burst; fire on the ground by zeds' feet leaves patches that last about 2 seconds.

Incendiary Trench Gun: use it for ranged ignition or impact damage; use its spread to light several zeds. Ground fire from it is very short.

Flamethrower: 4 ammo per click, same ground-fire trick as the Caulk n' Burn. No alternate fire.

Microwave Gun: 3 ammo per click; the alternate fire damages and blows zeds backwards.

Molotov Grenade: good against large groups funneling through a choke because its fire lasts much longer than weapon fire patches, but impact damage is low.

The starting Fireman's Knife has a flashy inspect animation when you press reload at full ammo.

Weapon stats (from the Tripwire forums, as quoted in the guide)

Weapon	Key numbers
Caulk n' Burn	Impact 10 dmg, DOT x1.5 for 5 s (1 s interval); ground fire 10 dmg every 0.25 s, 1 m radius, 2.5 s life; ROF 857; reload 3.3 s; bash 15
Incendiary Trench Gun	10 pellets x 15 dmg, penetration 3; afterburn DOT x1 for 5 s; ROF 77; first shell 1.67 s, next shells 0.55 s; bash 20
Flamethrower	Impact 25 dmg, DOT x0.6 for 5 s; ground fire 10 dmg, 1 m, 2.5 s; ROF 857; reload 3.66 s; bash 15
Microwave Gun	Wave 20 dmg; blast 200 dmg, 7.5 m radius, 60 degree angle; splash 20 dmg, 4 m; ROF 857; reload 3.3 s
Molotov	Explosion 60 dmg, 2 m radius; 5 residual flames, 10 dmg each, 1.5 m, 5 s

Flames keep damaging after firing without consuming ammo. Splash from the Caulk n' Burn does no damage to the shooter; the Flamethrower splash hurts the shooter at x0.35.

Skills

All preference, the author says. Their picks:

• Supplies: Fully Stocked (start with extra ammo and full ammo on any Firebug weapon bought at the trader; revisiting the trader does not restock). The alternative, Flarotov Cocktail, doubles the fire patch duration and lights up the area for 30 seconds.
• Spicy: Fuse (fire lasts 70% longer on zeds) or Heatwave (pushes zeds back for buffer space). The author mostly uses Heatwave since constant reapplication overshadows Fuse.
• Burn: Zed Shrapnel (50% chance a zed killed by fire weapons bursts into chunks, clearing waves and chain reactions; only with perk fire weapons) or Zed Napalm (burning zeds spread fire to nearby ones, saving ammo and money).
• Flame: splash damage seems negligible except with the Microwave Gun; range matters for the Caulk n' Burn and Flamethrower, while the Microwave Gun loses damage with distance.

Playstyles

• Full mobility: spray fire and keep moving. Good solo or when the team moves as a unit.
• Zoning: stay mobile near a position, slowly clear chunks, then move to the next one to hold.
• Turtle: defend a room in the classic hold-out style.

Comments add that the Flamethrower has better range than the Caulk n' Burn.

Related pages: Firebug guide: weapons, skills, loadouts and Caulk n' Burn tap-fire guide.