From Rick:

Immortal characters can be interesting and challenging for a writer to deal with in fiction. Anytime a writer decides to put an immortal character into his fiction, a number of problems and challenges will confront him. The biggest one is that if the character is truly immortal, he (or she) cannot die or be killed. This is fine if the character is passive or a minor one, but passive characters are rarely interesting, and if the character is minor, then what role does that character play along with main character?

If the immortal is a main character, then any fights or battles the character is in cannot lead to him dying or being injured, thus immediately reducing any potential tension, and if he is evil and a real problem for other characters, then being immortal leaves little room for dealing with that character.

That’s far from the only problem facing the writer. In order to properly develop any story, backstories should be developed as well as the reason immortal characters exit in your world. We’ll talk more about that later.

Let’s use the example of the character of Q, who first appeared in the Star Trek: The Next Generation series. While it’s never specified that Q is immortal, he is certainly nearly omnipotent. As Wikipedia states of Q: “He is an extra-dimensional being of unknown origin who is unconstrained by, and possesses immeasurable power over, normal human notions of time, space, the laws of physics, and even reality itself, being capable of violating or altering any or all of them in unpredictable ways with a casual thought or hand gesture, limited only by his imagination.”

Fortunately, Q is not evil, not in the sense that he intends permanent harm to other beings (and he has a sense of humor). It’s made clear in later episodes in the various Star Trek series that he is answerable to his fellow Q beings. In other words, his power, while nearly unlimited, is not absolute.

This brings up the point that if you do plan to include immortal beings in your story, then you should not give them unrestrained power as well—or at least give them a strong moral sense. It would not be wise to create an immortal who has god-like powers and who could create or destroy on a whim. Such a ploy could well lead to a boring story with few or no surprises. An interesting immortal character will have limitations of some sort.

Before we get to that, let’s take a look at the concept of immortality and its potential limits. The dictionary definition of “immortal” is “exempt from death or not subject to death; undying.” I will refer to this as “unconditional immortality.” The reason for that classification will become clear.

This leads me to propose “conditional immortality.” By this I mean that the character can somehow die, be killed, or be made non-immortal. Indeed we have in literature a number of such characters. While technically vampires are already dead, their status as “undead” makes then effectively alive in the sense that they act as a living being would. But they can be killed in the sense of being destroyed.

I’m going to suggest three types of conditional immortality. These are not always mutually exclusive.

(1) Immortal as long as they fulfill some condition.

Classic vampires fall into this category. They are immortal as long as they do certain things (for example, drink blood, sleep in native soil, avoid exposure to sunlight, not staked through the heart or cremated).

Another example of this type of conditional immortality is Dorian Gray in Oscar Wilde’s famous novella The Picture of Dorian Gray. Dorian made a deal with the Devil to create a painting that would take on the sins and age of Dorian (and turn hideous in the process), while Dorian remained ageless and effectively immortal—as long as nothing happened to the painting (which he kept well hidden).

We’ve also seen characters who keep themselves young by taking the lives or souls of mortals. As long as they do this, they remain alive and do not age.

(2) Immortal until a certain event occurs.

This event could mean their death by special means or if some other event occurs that terminates their immortality (but not necessarily their life). Depending on the writer, werewolves might fall into this category, being killed only by silver weapons.

In the Greek and Roman myths, immortal characters have been made mortal for various reasons, and immortal gods can only be injured or killed by other gods. In other words, immortal until their immortality is revoked.

Frankenstein’s monster was effectively immortal, subject to death only by burning. In the original Mary Shelley novel, the monster’s fate is ambiguous at the end (presumably from in the Arctic).

(3) Time-limited immortality.

The character’s immortality is limited in time. This may sound like a contradiction, but it’s not. “Immortal” does not mean that someone can never die, only that the character cannot die while the immortality is in effect. A good example is Dr. Who. He’s not strictly immortal, but if he dies, he regenerates into a new life and body. However, the Time Lords, of which he is one, have a limited number of regenerations, after which they are truly dead.

A writer who decides to use an immortal being or beings should set up the rules from the beginning to ensure internal consistency and logic. This principle is part of the world-building for any fictional setting where things deviate from the world as we know it. This includes the following if any of them exist in your world:

—How magic and advanced technology might work

—The use and limitations of superpowers

—The rules that govern the abilities of your various creatures (including vampires, shape-shifters)

You don’t need scientific explanations for everything, but you do need consistent reasoning behind everything. Readers will quickly spot inconsistencies and dock you for it.

But let’s return to our topic of immortality.

Answering the following questions should help you focus on your immortal character’s situation and provide backstory.

What is the source of immortality in your world and in the character?

Is there more than one immortal in the world? Are they equal in status and abilities?

Why is your particular character immortal?

Was he always immortal?

If the character was not always immortal, why or how did he become immortal? Was the immortality a gift, a curse, or a punishment?

Curse and punishment are not always the same. A curse may come about inadvertently—the character did something he (or she) should not have done. As a punishment, immortality can be bestowed for disobedience (character is doomed to repeat a mistake or watch others suffer as a result), or it could involve a torture (character doomed to burn in Hell eternally or suffer torment without succumbing to it).

Can the character’s immortality be lost or revoked? If so, how or under what conditions?

How does the character feel about being immortal? How does being immortal alter the character’s decisions and reactions?

What are the character’s limitations with regard to being immortal? Does being immortal somehow prevent him from doing certain things? For example, the character may be immortal but can only observe and not intervene in the physical world (and maybe if he does, he loses his immortality).

Does the character possess any additional special abilities or powers besides being immortal? (Be careful when giving an immortal character too much power because you have to deal with a potentially unstoppable being.)

Is the character truly immortal or just nearly so? (He might eventually die but his life span is so long that it’s measured in millennia or longer.)

If the character is not a true immortal, what are the character’s vulnerabilities? (Don’t confuse immortality with invulnerability. Superman is invulnerable to most things, except to kryptonite and magic, but he is not immortal.)

Finally, what are the effects and consequences of the character’s immortality on him personally? One obvious answer one is he will see friends die while he lives on. Perhaps this was his punishment.

Another consequence could be procrastination. The character intends
to do something (or is supposed to do something) but puts it off because it’s not pressing, and he knows he has all the time in the world to do accomplish it, but he puts it off too long and he now has a significant and difficult problem difficult to deal with as a result.

If you’re going to use immortal characters, give them interesting backstories. Use your imagination. You can make their backstory a mystery. Perhaps by becoming immortal they lost the memory of their past, and perhaps that was the intent when they were made immortal. Giving your immortal a difficult choice can be a good source of conflict and tension in your story.