Torzax sighed. He had travelled for many months in search of the evil Quorxkili, the sorcerer who had ordered his family slain when Torzax's father would not give him his eldest daughter to wed. His companions, Eldnor the gentle healer and Norlax the mage had suffered much in aiding his quest. And now, when it seemed that the quest was over they once again had only discovered another of Quorxkili's abandoned keeps.
A flash of light! A sound like a clap of thunder! Suddenly the evil mage was before them. "You bother me!" he scowled as glowing energies lashed out from his hands and engulfed Torzax. Eldnor and Norlax were stunned; but Torzax, though injured, howled in rage and attacked the sorcerer. His sword burst into flame as he rushed Quorxkili, knowing that only by attacking him suddenly with magical fire could he kill him before the mage blasted the life out of him. His sword moved like lightning, preventing the wizard from casting another spell or even effectively defending himself. Quorxkili, his flesh horribly burned, dropped motionless to the ground.
"They are avenged!" Torzax shouted in triumph over the body of his foe. In his exultation, he failed to note the building glow around Quorxkili. Norlax, suddenly able to see what was happening tried to cry a warning. But before he could say a word, a blinding explosive flash burst from Quorxkili knocked Torzax twenty meters into the air. He fell in a sickening "thump" to the ground, his body reddened by the strange magical force. Eldnor ran to him. "He...he...he's...dead!" she said.
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Here we have a character that has been played for several sessions, raised to high levels or skills, killed just as he achieves a major character goal. The player should be happy that his PC got to go out with a bang and just roll up a new character, right?
Well, after one has suffered with a character for an extended time, built him up from his puny beginnings, and finally achieved a heroic level of power one may not want to start over. Not just because a new character will likely be weaker, but because the old character has grown and developed. So most fantasy role playing systems allow for the possibility of Resurrection; bringing a character back from the dead.
THE SPELL
Eldnor laid her hands on the motionless body of Torzax, and looked to the heavens. As she called on the power of healing magics, a faint glow went from her hands to engulfing the hero's limp body. With a gasp, and a sudden jerk, Torzax returned to the lands of the living. Eldnor embraced her friend and lover.
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Here's a problem. When Resurrection is this freely available death becomes essentially meaningless. Eldnor's distress at Torzax's death is short term because she knows that she'll just raise him again, and again, and again. It also detracts from the heroism or foolhardiness of Torzax's charge of the sorcerer. He knows that if he dies, it will only be temporary. Other than the pain, death is just an inconvenience.
Now if the spell is only recoverable by some great sacrifice, or requires a sacrifice at the time of casting it becomes more meaningful and will perhaps make our healer think seriously before performing resurrections. The sacrifice could take the form of life energy (POW in RQ or Call of Cthulhu, maybe a level in level based systems) or physical attributes.
THE PROFESSIONALS
Eldnor threw herself across her lover's body. She cried until the tears would no longer come. "We must take him to the high healers!" she told Norlax.
"But that will take all our earnings for the last year!" he said. Eldnor's glare at that comment was perhaps the most frightening thing he saw that day. And in his heart of hearts, he knew that he owed Torzax and wanted him back at his side.
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Perhaps Resurrection is only possible from certain priests or sorcerers. In that event, it will likely be expensive. Not necessarily in money; the priests may have some other mode of payment in mind. Our heroes could find themselves committed to a quest more dangerous than the pursuit of an evil sorcerer. And it is entirely possible that the priests will reject the request, leaving the party to haul the body to another group of priests that might be more willing or perhaps desperate for heroes to perform a quest.
THE QUEST
Eldnor and Norlax sat by Torzax's lifeless body in mourning. "How can one be brought down in the prime of life? It isn't right!" Eldnor said. Norlax grimly said to her, "There is a way to bring him back. But if it fails, we shall be in the land of the dead; with him or...elsewhere." Eldnor took his hand. "I am willing", she said.
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It is entirely possible that to resurrect someone it would be necessary to find the person's spirit in the spirit plane (netherworld, afterlife) and bring them back to their body. Usually one would need assistance from some sort of specialist, but it is possible that a party member might well know the rituals, spells, or even a place on the physical plane where it is possible to go to the spirit realm or wherever the dead go.
There's problems with this of course. Our heroes have to deal with the rulers and/or residents of this place. They might not like people leaving, or they may require some sort of payment. It might be a very expensive payment; more of those deadly quests, perhaps. And it is also possible that the spirit may be perfectly happy in the afterlife and not want to come back. Plus of course there's always the possibility of some sort of condition set by the rulers of the realm or the natural laws of the place that must be upheld for the spirit to return. Remember Orpheus; don't look back.
THE CHANGED
Eldnor stood by the campfire, lost in thought. She was keeping watch as Norlax slept, but her mind was on her lost love Torzax. Then she heard a twig snap. She turned, and started to shout an alarm when she heard a familiar voice.
"Quiet, you'll wake him. You know how grumpy Norlax gets when he's woken unnecessarily."
"Torlax? You're dead!"
"I got better."
She rushed to embrace him, not caring for the moment just _how_ he came back. He kissed her, and then whispered in her ear, "Do not be afraid. I only need a little." She wondered why he said that...until she felt Torlax's sharp fangs bite into her neck and his month sucking, drawing out her blood. Sated, Torlax said, "It is nearly sunrise. I must be going; but please remember I would never harm you. I will always be with you."
Later that morning she found no wounds. She thought that it was a dream, until she noticed a tiny blood stain on her collar and a wild red rose of the type Torax always gave her when he felt romantic. She wasn't sure whether to be happy or terrified.
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Here we have a rather odd sort of "resurrection". Somehow, the spell that "killed" Torlax actually turned him into a vampire. A very mild sort of vampire that doesn't need to kill to survive, but still a vampire. In this case our heroes do not need to take any action to raise him from the dead, but they may be inclined to return him to the grave.
Of course it's possible that our fallen comrade might not come back in a benevolent form. In AD&D, Eldnor would have lost a level feeding Torlax unless the DM used a radically different vampire; there isn't a nice way for a vampire to feed. And it's possible that the change to undead status might change the character's personality and temperament. Torlax might be gradually turning Eldnor into a vampire. Or he could have come back and used her initial joy at seeing him to get in close enough to rip her throat out.
This is a bit of a difficult one to pull off, I suspect. Many adventuring parties would just whip out the stakes and kill their one time comrade. Other sorts of undead other than vampires would be possible here also, but of course they'd need to be intelligent varieties. It wouldn't be much fun playing a mindless zombie, after all.
And of course our fallen hero may come back from the dead without being an undead. He may not actually have been dead; the healer may have missed signs of life in her distress or willfully ignored signs of life out of a desire to see him dead. Or he could be some other sort of being; an Immortal like on Highlander perhaps.
THE ABANDONED
"Are you certain Torlax is dead?" Norlax asked?
"Yes, absolutely", Eldnor said sadly.
"That means...we can finally be together!" Norlax cried.
They rushed into a passionate embrace filled with long suppressed desire. "But wait", Eldnor said, "there's something we must do."
"Of course", said Norlax. The two then proceeded to strip Torlax's body of all his material possessions.
The next day, the new lovers came across a young warrior who looked lost. "Do you know the way to Ess Tra?" he asked.
"We happen to be heading in that direction, and we could use the company and the assistance in carrying some equipment", Norlax said. The young warrior gladly joined them, and carried the last possessions of Torlax for them other than the great magic blade Flamestrike which Norlax wore.
He looked at Flamestrike longingly. "Mighty fine sword you have there", he said.
"Yes", Norlax said, "it belonged to a late friend." Norlax noted the strange resemblance between the young warrior and Torlax in his youth. Maybe he'd become worthy of this sword, he thought, but this time Eldnor is mine.
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Sometimes, the survivors of the party are just not going to want to resurrect their fallen comrade even if it is possible. They may actually dislike the guy. It may take more than they feel it would be worth. The deceased may have believed that once you die you should remain in your opponent afterlife. Or maybe, as in the above example, they had other desires that the dead character had interfered with or prevented.
In some cases the player of the fallen character may not want him or her resurrected; they may be leaving the campaign or they might want to try a new character. Even if the rest of the party resurrects them, it should be possible for the character to leave; you shouldn't force a player to keep a character just because the rest of the party has uses for them.
A bigger problem is when the player wants to continue playing the character but the rest of the party won't resurrect them. One option could be to have them come back as an undead; imagine the chaos if Torlax came back after Eldnor and Norlax became lovers! Or some other person or entity might resurrect the character for their own purposes. The problem is that if the rest of the party doesn't want this character in the party and that's why they didn't resurrect him there will be a lot of unease and potential conflict. There's enough that can go wrong with campaigns without more strains.
THE FINAL AUTHORITY
Eldnor and Norlax were distressed. The wizard Orlackoffann had told them that the magics that killed Torlax made resurrection impossible. There was nothing more to be done but to bury their friend.
They buried him the next morning with a lock of Eldnor's hair and a talisman for the dead from Norlax. They prayed silently to their various deities, and went sadly on their way.
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Ultimately and finally the decision on resurrection rests with the GM. How available do you want resurrection to be? Do you want death to only be a minor inconvenience that doesn't interfere greatly in the progress of the campaign? Do you want it to be a major undertaking, perhaps even an adventure in itself? Do you want it to not even be available at all; perhaps only a myth? And sometimes, even if resurrection is available, you may well not want a character resurrected. It may not make sense at that time for the character to be resurrected. The character may be disruptive and you may want him or her to stay dead. Or the player may want their character to stay dead. Well, come up with a good, game world consistent reason for the character to stay dead.