As a specific kind of undead the lich seems to originate entirely in the 20th century, without any clear ties to older mythology - if a powerful magician cheated death in most mytheia, he did it whilst still alive, not as an animate corpse. The idea of an animate, spell casting undead husk seems to originate in the works of people like Clark Ashton Smith and Robert E. Howard. The word itself is simply the old English for a corpse - many churches in England still have a lych-gate leading to what used to be called the lych-yard through which lyches would be carried for burial.
The best known source of liches in modern fantasy is probably the Dungeons and Dragons ruleset, which adds the further refinement that the lich has removed his soul (or other source of lifeforce) and stored in a repository of some kind (called a phylactery in the D&D rules). Gary Gygax has stated that he based this on the short story "The Sword of the Sorcerer" by Gardner Fox, but this idea has echoes of Koschei the Deathless from Russian mythology, of some Egyptian magical concepts and, quite possibly, other European influences where a magician removed part of himself1 to make himself unkillable. It also bears more than a passing resemblance to J.R.R. Tolkein's Sauron.
Rolling with the D&D concept, the phylactery makes the lich effectively indestructible as well as undead - if his body is destroyed he can either re-form it at the phylactery (D&D style) or at least persists and is able to possess a suitable living or dead host given the chance. For players who are not genre savvy - or at least don't know what it was they just fought - the return match against the now even angrier lich can be an unpleasant surprise.
Unsurprisingly a lich tends to be a master of necromancy and is thus able to back up his formidable magical prowess with shambling hordes of undead. He tends to be a prime candidate for the role of thanatarch of any thanotocracy that happens to be going.
Game and Story Use
- The Lich is a BBEG par excellance. Subvert this and give the PCs one as a patron.
- Even having one that is not immediately hostile would be a subversion. Seriously, not everything in your campaign world - not even the undead - need necessarily be put there so that your PCs can kill it.
- The hunt for the phylactery is probably more of a quest than the hunt for the lich - indeed without having located and destroyed it, an assault on the lich is probably futile, or at best no more than a spoiling attack.
- For bonus annoyance, make the phylactery something the PCs will not guess at easily - or something they will have serious qualms about destroying: perhaps part of their patron's crown jewels (if the lich is old enough; perhaps he presented the jewels to the patron in life, or allowed them to be taken as a trophy2) or the keystone to something (literally for a significant piece of civil engineering like a dam or figuratively for a ward that holds shut a gate to somewhere truly terrible or contains sealed evil in a can
- Conversely, a lich could serve as sealed evil in a can if his phylactery was secured in such a way that he couldn't re-form and then his body destroyed. Sooner or later some PC loots the shiny phylactery, removing it from its containment, and then either ends up hosting the lich's spirit, or allows it to reform wherever he leaves the phylactery…
- This can get a bit tricky if the lich has forgotten what its phylactery is. It knows how phylacteries work, but it doesn't have any more idea where the thing is than the PCs do.3 A few possibilities:
- The lich forced itself to forget, so that it couldn't be tricked, mindscanned, or threatened into revealing the thing.
- Something traumatic happened to the lich involving the phylactery, and now it has a memory block.
- The lich hasn't seen the thing in centuries (either because it hasn't needed to regenerate or because liches in your campaign don't regenerate near their phylacteries), and ever since fate has conspired to keep the lich from noticing the one thing that is always around when it regenerates.
- Most players are genre savvy - use this against them. Either disguise a lich as something else, or disguise something else as a lich.
- Show how powerful something is by giving it liches as servants…
- An involuntary lich could make a very sympathetic character.