Real people don’t often make it through two consecutive days unscathed, much less a week (at the very least, there’s going to be a mosquito bite, a burnt tongue, a stubbed toe, a hangnail or a paper cut), so it’s unrealistic to expect the people who live in your novel to do so. Nevertheless, it’s a mistake to people a story with “whipping boy” characters, whose only purpose is to suffer injury in order to distract from the fact that the protagonist and antagonist escape harm.
Whatever physically or psychologically happens – or doesn’t happen – to a fictional character needs to pass the plausibility test: Is this something that can be reasonably expected to happen – or not happen – to this character under these circumstances?
For example, it’s the worst of “magical thinking” on the part of a writer to send characters into fistfights and bring them out uninjured. At the very least, people who engage in fisticuffs get face and/or body bruises and/or cuts, broken hand and/or facial bones, and loosened teeth.
It also takes time for a person to recover from the damage incurred by a fight: Cuts take days to heal; bruises take weeks to fade, bones take weeks to months to mend. Hand-to-hand fighting also affects the muscles and joints, so your fictional pugilist will be acutely achy for some time afterwards. A period of recuperation must be reflected in the activities of the character for the foreseeable fictional future.
Not all fictional characters need to engage in physical violence to experience pain and rack up scars: Age takes its toll, too. For example, most of the main and strong secondary characters in Irish Firebrands are middle-aged or a little older. They exhibit the usual range of ability and appearance for persons who are 50 to 62 years of age: some are quite athletic and others are less so, but all of them show their age in one way or another (if only because of graying hair or baldness, crows’ feet, and a bit of middle-age spread), and they are susceptible to environmental exposure and accidents.
Female main character Lana Pedersen falls and bloodies her nose, and she also comes down with a cold, but it’s Dillon Carroll, the male main character in Irish Firebrands (and one of the oldest characters) who really takes a beating in the book. He lives an active life as a journalist, but he’s still susceptible to sunburn and sore joints; he gets winded climbing a mountain, and his legs ache when he descends the steep slope; he receives bruises and scrapes from flying debris and suffers temporary hearing loss when he happens to be in the vicinity of a suicide bomber. In addition, both characters suffer mental pain from long-term, untreated psychological problems.
It may be a temptation to avoid the built-in consequences of aging by writing only about youthful beings, but just because characters are young – whether or not they’re human – doesn’t mean they’re immune to injury and bodily or mental pain. Even Superman had his own painful run-ins with kryptonite. Inexperienced young people often do behave as if they were invulnerable to physical and psychological harm, but eventually the bumps and bruises of real life catch up with them. Realistically portraying the thorny path to maturity for a young person has innumerable fictional examples: Scarlett O’Hara of Gone With the Wind comes to mind, as does Medb McManus, the strong secondary teenage character in Irish Firebrands.
The Right Character is one who is believable, and that means he or she has an Achilles’ heel. Give him or her eyeglasses to wear, a medication to take, a phobia, and show readers how he or she gets some of his or her visible and invisible scars. The root of the word “novel” comes from the concept of “new:” in novels, imperfect characters experience renewal through overcoming their imperfections.
And that’s the real reason why we want to read about them.