Crimson Death Mist

Hungry, a crimson death is a faint, colorless cloud in the rough shape of a person, with a dim hint of a face. Against fog it is nearly impossible to spot and infravision barely shows it. Fed, it darkens to a deep red anyone can see. While it eats, its fingers stretch into long misty tentacles. It whispers almost inaudibly, can converse with air elementals and other gaseous beings, and talks to humanoids only when their prisoner.

It attacks only to feed or defend itself, gaining +4 initiative while pale. Tentacles of vapor wrap the victim, and each hit drains bodily fluids for 3d10 damage.

Unfed it is immaterial, AC 0, harmed only by +2 or better weapons. For six turns after a meal it is solid and red: flight slows to 6, AC worsens to 4, and +1 weapons can hit it. Destroyed, it scatters on the wind while its undigested meal splatters to the ground.

It can levitate whatever its body engulfs and has the strength of an ordinary human, enough to carry a limp adult. A struggling captive requires a successful attack roll each round or falls, taking damage for the drop.

Cold, wet bogs and marshes are its home. It hunts by stealth, preferring lone travelers; facing a camp, it takes the watchman first and then feeds on the sleepers. It hides bodies in deep bog or its lair, a thicket, undercut bank or hollow under deadfall, where it hoards victims' valuables to bribe humanoid allies or lure prey. It wants humanoids, one a week, but will gorge on more if available until killed or driven off.

A crimson death survives unharmed sealed in an airtight vessel, where it may pass for a bottled djinni or magic vapor, and attacks whoever frees it. It makes eager allies for evil humanoids who keep it fed.

Many tales link it to vampires: that it is the spirit of a destroyed vampire, or a new vampire's lost soul reborn elsewhere, whose reunion with its vampire might restore it to life. Another holds that the vilest air elementals are exiled to the Prime Material Plane in this form.