Negative Fundamental

Each is a scrap of the Negative Energy Plane shaped into a pair of flapping, bat-like wings, flat black and without body or face. They fly through that void in vast flocks called murders. They are barely intelligent and have no language, but a faint empathic link lets a murder wheel as one, and each senses every kin within 100 feet.

They feel living things within 100 feet and drop on them as a flock. In dim light, their color imposes a -2 on opponents' surprise checks. A ramming touch drains 1d6 points of life.

In 30% of encounters a murder teems, mobbing one victim so thickly that each fundamental's THAC0 improves by 1 per participant, down to a limit of 5. Ten teeming fundamentals strike at THAC0 9 rather than 19. Teeming lasts 1d4+4 rounds.

Only magical weapons harm them, cold and mind-affecting powers do nothing, and 10% of spells cast on them simply drain away into their bodies.

They rarely leave their plane, but the making of a powerful undead can pull 1d10 of them through. A newly risen vampire, for example, forges its first link to negative energy, and a murder may follow that channel so that a burst of black wings erupts as the vampire leaves its crypt.

At home their plane sustains them. Elsewhere they must feed on life. One that absorbs 6 or more points weekly for six straight weeks has a 50% chance of splitting into two identical fundamentals; one that gets less than 6 points in any single week away from home evaporates.