Oops They’re Regenerating!

Last Updated: 190623…200704

The question arose of exactly how one kills a troll:

“To kill a troll, the monster must be burned or immersed in acid, any separate pieces being treated in the same fashion or they create a whole again in 3-18 melee rounds.”

How exactly does that work? Does the troll only need to be burned after it reaches 0 hit points? Must all damage dealt be from fire? Will fire damage not regenerate? Does other damage therefore regenerate?  As with most things AD&D, the rules don’t dig into the implementation.

A review of regeneration leads only to more questions!  All regeneration ability is not the same. Regeneration can include the recovery of hit points, restoring life from death, the regrowth of lost limbs, and the animation of severed limbs, although few creatures (or items) combine all of these powers. Given that specific facets of regeneration are specified for individual creatures, the assumption is that regeneration abilities not included in a description are not in effect.

The recovery of hit points via regeneration is represented by number of hit points recovered per round (or turn). In rare cases regeneration prevents death (or at least restores the creature to life), but for the vast majority of cases, regeneration begins (or is triggered) when the creature is wounded, and ends upon the creature’s death (0 hit points). The regrowth of appendages typically takes days, and is generally independent of hit points. In some cases regeneration includes the animation of lost limbs, which can either slither back to their host or, in some cases, attack independently!

Regeneration can also include specific limits. Some creatures don’t regenerate for [n] rounds after being wounded. Others can’t regenerate damage from a specific source (fire, acid, etc.), or require specific circumstances to regenerate (e.g., immersed in water, or in lava). Other things that can affect regeneration (creature-dependent) include: if immersed in water, fire, lightning; acid; silver; holy water; holy weapons.

Rates of regeneration:

  • Regenerate 7 hit points per round: Solar
  • Regenerate 4 hit points per round: Planetar
  • Regenerate 3 hit points per round: Vampire, Ixitxachitl (vampiric), Troll*, Revenant*, Slaad (Red)
  • Regenerate 2 hit points per round: Jubilex, Pit fiends, Son of Kyuss*, Ice Troll*, Mephit*
  • Regenerate 1 hit point per round: Ice devils, Lemures, Imp, Quasit, Pazuzu, Bael,Titivilus, Ogre Magi*, Tarrasque*, Abishai*, Nupperibo*, Giant Two-headed Troll*
  • Regenerate d12 hit points per turn: Amon
  • Regenerate 3 hit points per turn: Mycadaemon
  • Regenerate 2 hit points per turn: Glasya
  • Regenerate 1 hit point per turn: Shade, Willow, Black
  • Regenerate up to 20 hit points per day: Nabassu

* With conditions

Magic and Regeneration

Ioun Stone (pearly white): Regenerates 1 hp of damage/turn. Does not restore from death, nor regrow limbs.

Flame Tongue: +2 vs. Regenerating Creatures: +2 versus a creature with any facet of regeneration. Given the explicit flame on the blade, creatures with the ability to regenerate but affected by fire would be affected by this blade.

Regenerate (spell):
“body members (fingers, toes, hands, feet, arms, legs, tails, or even the heads of multi-headed creatures), bones, or organs will grow back. The process of regeneration requires but 1 round if the member(s) severed is (are) present and touching the creature, 2-8 turns otherwise.”
Does not include the regeneration of hit points, limbs reattaching, or restoring life after death.

Regenerate (Major Artifact Benign Power): “2 hp/turn (but not if killed)”.
Does not include the regeneration of limbs, or restoring hit points after death.

Mighty Servant of Leuk-O‘regenerates (self-repairs) 2 points of damage per round to itself.” If the device is destroyed, regeneration will stop.

Ring of Regeneration:
“The standard regeneration ring restores 1 hit point of damage (and will replace lost limbs or organs eventually also) per turn. It will bring its wearer back from death (but if poison is the cause, the saving throw must be made or else the wearer dies again from the poison still in his or her system). Only total destruction of all living tissue by fire or acid or similar means will prevent regeneration.’

If a character wears a Ring of Regeneration, are they killed but restored to life, or never actually killed? It’s a subtle but important distinction. Clerics changing alignment are killed by their deity. When a character is drained of all energy levels, he or she might become an undead monster of the same sort which killed him or her. The Censer of Summoning Hostile Elementals could burn until the summoner is killed. Will the Ring restore them to life? The DMG states: “Any character killed and subsequently restored to life by means of a spell or device, other than a ring of regeneration…” implying that a killed character can be restored to life by the Ring of Regeneration. The PHB, on the other hand, states: “Certain magical means will prevent actual death, particularly a ring of regeneration”, so a Ring of Regeneration’s effect is to prevent death.

After all that study, still no closer to determining the specifics of how to kill a troll!

Looking sideways at BEMCI, the regenerating hydra cannot regenerate damage done by fire, and trolls cannot regenerate damage from fire or acid, implying they regenerate all other damage. In 2e, fire and acid damage cannot be regenerated, because that damage is more extensive than normal wounds. Also in 2e, only total destruction of all living tissue by fire or acid or similar means will prevent regeneration for the Ring of Regeneration.

Returning to 1e, the giant troll—which does not regenerate as well as a normal troll—must receive at least 10 hit points of damage by fire; if this condition is not met and the giant troll is reduced to a single hit point, any further damage on it has no effect save to negate regeneration.


Regeneration heals damage. Regeneration won’t restore life unless the associated features of that specific regeneration include that ability—Trolls have that ability. Given that giant trolls require at least 10 hp of the total damage to be fire to be killed, and their regeneration is weaker than the standard troll, the standard troll would require all hp of damage to be by fire or acid before it is killed. Fire/acid damage won’t regenerate. Non-fire damage will regenerate.  While hit points are an abstraction, for regeneration, only damage caused by fire and acid (or other sources depending on the monster) causes actual, permanent, damage. The rest can be regenerated.

What happens when the players later want to heal a troll is a question for later …

Appendix A: Monsters and their Regeneration

  • Aleax: regenerates after being first wounded; the round after the wound is taken, it regenerates 1 hit point, the next round 2 hit points, then 4 hit points, then 8 hit points and so on until it is killed (reduced to zero hit points or below) or all hits are restored. If it is then hit again, the progression starts again at 1 hit point;
  • Creatures from the Lower Planes: Regeneration base is 1 hit point per turn, with exceptional creatures having a maximum of 1 per round.
  • Abishai: regenerate at the rate of 1 point per round, unless struck by silver, holy water, or holy magic weapons.
  • Achaierai: An injured leg will regenerate fully in about two days but the birds do not possess other regenerative powers and a leg which has been completely lost will not be re-grown.
  • Beholder: lost eyestalks will eventually grow back (1 week per lost member).
  • Froghemoth: Injured members heal or regenerate in 2-5 weeks.
  • Grell: Any hit on a tentacle will render it inoperative (though if the creature survives, the tentacle will regenerate in 1-2 days) but the damage is not subtracted from the creature’s hit points—only by hitting the body can the grell be damaged in the usual way.
  • Hydra (Lernean): Each time a head is cut off (or killed), it grows two new ones in d4 melee rounds unless fire is applied.
  • Mephit: Regenerate 2 hit points per round (if in contact with the lava).
  • Nonafel: Regenerate 9 hit points each round (one for each of 9 offspring).
  • Nupperibos regenerate at 1 hit point per round. If a holy object (water, weapon) is used against them, regeneration is not possible.
  • Ogre magi: 1 hit point per melee round (lost members must be reattached to regenerate).
  • Portuguese man-o-war: Tentacles will regenerate in several days.
  • Revenant: Limbs function independently. Limbs will slither back together. Regenerate 3 hit points per round after death, except by burning.
  • Slaad (Red): Regenerate while still alive at the rate of 3 hit points per melee round.
  • Ssendem (Slaad Lord): 3 hit point per melee round while alive.
  • Son of Kyuss: 2 hit points per round; its limbs will regenerate if severed, like those of a troll. Even after ‘death’ this process will continue,, so the only way of destroying these creatures is by fire, lightning, acid or the application of holy water to their wounds.
  • Spectator: Eyes regenerate in 1 day.
  • Tiamat: Head(s) replaced the following day.
  • Tarrasque: 1 hit point per round. Even the slightest piece will regenerate and be restored completely.
  • Thessalhydrae: Fringe heads regenerate in 12 days.
  • Troll: 3 melee rounds after being damaged, repairs damage at 3 hit points per round; this regeneration includes the rebonding of severed members. The loathsome members of a troll have the ability to fight on even if severed from the body; a hand can claw or strangle, the head bite, etc. Total dismemberment will not slay a troll, for its parts will slither and scuttle together, rejoin, and the troll will arise whole and ready to continue combat. To kill a troll, the monster must be burned or immersed in acid, any separate pieces being treated in the same fashion or they create a whole again in 3-18 melee rounds.
  • Troll (Giant): Before a giant troll can be killed, at least 10 hit points of damage must be inflicted on it by fire. If this condition is not met and the giant troll is reduced to a single hit point, any further damage on it has no effect save to negate regeneration.
  • Troll (Giant Two-headed): They regenerate as do trolls but at the rate of 1 hit point every melee round, though they cannot re-bond severed limbs.
  • Troll (Ice): regenerative powers of a normal troll but at a rate of 2 hit points per melee round, so long as the regenerating members can immerse themselves in water. A severed limb can move a distance of 30′ in search of water and will always move towards water if there is some in range.
  • Troll (Spirit): It regenerates as does a troll, and at the same rate (3 hit points per round).
  • Troll (Freshwater/Saltwater or Scrag): Regenerate as trolls but only when immersed in water
  • Wolf-in-Sheep’s-Clothing: can regenerate appendages in 1-4 weeks.

Author: Rick

A DM for *mumble* years, I've been playing AD&D since junior high. I've currently got two separate campaigns running, both in Mystara. I've been told when they handed out hobbies, I stood in the short lines. I actively cycle tour, kayak, play board games, read, develop home automation software, volunteer with the American Red Cross, and work on a never-ending stream of home repairs. In my wake I've left paintball, medieval full-contact combat (SCA), computer gaming, Heroclix, tablet weaving, and kite construction.

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