Posilich, stage 1 

*If no optional rules for monster statistics are used, consider that the Posilich has a bonus to hit points for each hit die equal to that of a warrior with 20 CON.

The positive lich or posilich was created for the first time by Man-Laiter. The sorceror feared for his life because of a dire disease, and wanted immortality at any cost. However, he feared to become a lich, so he searched in another direction. Man-Laiter asked himself: "A lich is sustained by the Negative Energy Plane. In theory, the Positive Energy Plane should be just as good in sustaining life, if not better?". At this stage of research, Man-Laiter hasn't yet experimented this procedure on himself, but he tried many times on people he captured near his place. The exact procedure is known only to him, but it should be similar to the one used for "normal" negative liches. The process at this stage is almost lethal for the subject's mind, and the resulting creature isn't half as powerful as a true lich. A psilich is a humanoid, which emanates an intense light on all its body. This light doesn't feel unholy or evil, but it still gives a feeling of danger. The touch of a Posilich channels in the body of the victim, even through armor and shield (if they are made of organic material), an enormous amount of energy from the Positive Material Plane. A mortal body isn't fit to hold this energy. The effect on a human is an adrenaline discharge, and an immediate acceleration of the hearth pulse; mental processes are interrupted and after a while the energy is too much and causes a collapse and the death of the victim.

When a person is hit by the posilich, he must save versus paralysis; if he fails, he falls to the ground and is practically paralyzed until the posilich lifts the grip. A "common" (without Negative Plane contact, such as skeletons, zombies and ghouls) must roll a ST versus death or be annihilated. An undead such as a vampire, spectre or lich is more resistant, because it can cancel out the positive energy with the negative one, but it still suffers twice as much "damage". In any case, the victim suffers 2d6+2 "damage"; the posilich's "damage" are in fact negative energy, so they mustn't be subtracted to HP but added. The character's wounds are NOT healed: if he suffers additional normal damage beyond his maximum HP, he dies anyway! When the positive energy points total reaches twice the normal HP, the character immediately dies due to hearth collapse. The posilich, after having hit, usually maintains the grip. Subsequently, it works as if it hit automatically every round. Even if the posilich's arm is severed or the creature dies, the grip remains (but should the posilich die, the damage stops). To pull away the arm a Strength check against the posilich's strength is required, and the one touching it suffers the same effects of the touch.

For example: a warrior with 36 maximum HP (he now has 25) meets a posilich. He is hit and the posilich inflicts 8 points: now the warroior still has 25 HP, but he also has 25+8=33 positive energy points.  If the warrior was hit with 12 common damage he would have 13 HP and 21 positive energy points. If he suffered 14 more common damage he would die even if he still had 7 positive energy points. Positive energy points are NOT hit points. If the warrior, while having more than zero HP, was hit by the posilich up to 36x2=72 positive energy points, he would die. Even if the posilich doesn't inflict real damage, if a character is hit while spellcasting, he normally loses concentration. The posilich can't be hit by nonmagical weapons, regenerates 7 HP per round, and is immune to charme, sleep, enfeeblement, polymorph, heat and fire, electricity, madness of any kind and death magic or energy drain. A posilich made from a common person has 5 HD, but a posilich made from a high-level character has HD equal to the experience level. A stage 1 posilich has no phylactery. The posilich isn't a true undead; it can be turned as a lich, but the priest counts as if he had two less levels and the creature can't be destroyed in this way. Man-Laiter is convinced that, in time, he will be able to find a procedure to become a posilich as powerful as a lich without losing his reason in the process. Meanwhile, he has already found a way to survive his disease.

Fonte: Zappo.