The fire vampire is a new vampire introduced in SLASH'EM. It uses the fire attack which is a deferred feature in vanilla NetHack, a counterpart to the Angel's magic missile attack and Asmodeus' cold attack. It appears to be Lovecraftian in origin.
The fire vampire can be very dangerous to the unprepared. It is very fast, with a speed of 24. Like all vampires, it has two claw attacks and a bite attack. It also has a touch that drains magic energy, and the ability to cast a spell that will cause you to be 'enveloped by flames!'. This attack can do upwards to 60+ damage without fire resistance. Note that at a distance they will zap fireballs at you. These cannot be reflected, and can still damage items in your inventory even if you have fire resistance. They are best avoided until you have fire resistance; in particular, they make the Chaotic Quest a place to avoid for those without it.
Oddly enough, fire vampires are not actually immune to drain life, as most other vampires are.
Encyclopedia entry Edit
A swirling cloud of bright, burning motes, the fire vampire
descends upon its victim and easily burns them to death once
they are in its deadly embrace.