Negative Energy Elemental

Built from the stuff of the plane of negative energy itself, these elementals take the form of roughly manlike curtains of jet-black fire. On any other plane, death and decay trail behind them.

Their presence alone is poison to life, harming everything within 30 feet of them. A negative energy elemental attacks either by shaping a fist and pounding its target or by washing over it in a pitch-dark wave. A hit deals 3d8 points of damage from dying cells and drains two levels of experience. Its touch also rots away anything of organic origin within a 10-foot cube, 1,000 cubic feet in all, such as cloth, wood, parchment or food, unless the item makes a saving throw vs. acid.

Being so bound to its plane makes it vulnerable to elemental forces. Any elemental or elemental being that attacks it gains +2 to hit and +2 damage per die, and the creature saves at -2 against elemental effects such as lightning bolt and fireball.

They never leave their plane willingly, but suitable spells or spell-like powers can summon them. A summoner who loses control suffers a backlash of negative energy and loses 1d4 levels unless a save vs. death magic succeeds. For three rounds the freed creature then assaults its summoner, after which it fades away to the Inner Plane that spawned it.

After more than a day away from home, a negative energy elemental must feed on life force. Unless it devours 10 or more hit points, or 1 level, daily, it returns to its own plane, so its hunger soon betrays any attempt to stay hidden.

Binding one into a magic item in exactly the right way, a hugely dangerous task, might turn its aura into a boon for a necromancer or other evil mage. Every month of captivity carries a 5% risk of escape. Once loose it can never be controlled and hunts the one who bound it until one of them dies.