Pyromaniac

Pyromaniac is a Fallout 2, Fallout 3, Fallout: New Vegas, Fallout Tactics and Lionheart perk as well as a Fallout: Brotherhood of Steel skill.

Fallout 2 and Fallout Tactics
In Fallout 2, the most violent fire-based death animation will always be used.

Fallout 3
With the Pyromaniac perk, you do +50% damage with fire-based weapons, like the flamer and Shishkebab.

Affected weapons

 * Shishkebab
 * Flamer
 * Firelance
 * Heavy incinerator
 * Rapid-torch flamer
 * Slo-burn flamer

Bugs

 * The Burnmaster, the Nuka-grenade, and the Zhu-Rong v418 Chinese pistol are unaffected by the perk. The guide lists these as being affected by this perk, but the weapons aren't on the form list - this is most likely an oversight by the developers.
 * The unofficial Fallout 3 patch fixes the oversight.

Fallout: New Vegas
With the Pyromaniac perk, you do +50% damage with fire-based weapons, like the flamer and Shishkebab.

Affected weapons

 * Flamer
 * Shishkebab
 * Incinerator
 * Heavy incinerator
 * Incendiary grenade
 * Fire bomb
 * Sonic emitter - tarantula
 * Sterilizer glove
 * Saturnite fist super-heated
 * Gehenna
 * Cleansing Flame

Affected ammunition

 * .50 MG, incendiary (burn damage only)
 * 40mm grenade, incendiary
 * 12 gauge, dragons breath

Fallout: Brotherhood of Steel
Each level of this skill increases your Critical Chance for +5% (up to a maximum +25) when using fire.

Points requirements

 * 1 Rank : 2 Points
 * 2 Rank : 4 Points
 * 3 Rank : 8 Points
 * 4 Rank : 16 Points
 * 5 Rank : 32 Points

Lionheart
You have a natural affinity for fire and a knack for setting things ablaze - especially other people. You get +10% damage with fire-based weapons or spells.

Piroman Пироман