Holly: Can he even drink? Like, booze? Caaaaaaassie! Cassie: It’s never come up before. He says at one point in the books that he could drink a little bit of coffee. Eating would make him sick.

Kelly: So no booze. No barbecue, Chicken McNuggets, or cotton candy. It’s a bit like keeping kosher only much, much worse. And of course, yes, blood isn’t kosher.

Holly : But blood is legendarily delicious in literature. I mean, Simon seems super into it when he’s drinking from a living person.

Kelly: I’ve never tried blood myself. Although I have had black pudding. Holly: I am willing to concede that Simon might have concerns about immortality, but he’s largely speculating about how it will go, since he’s only a few weeks into his new life. He hasn’t yet watched his family age and die. He hasn’t yet lost lovers.

Kelly: It does affect his relationship with his family, though. Becoming a vampire—being an immortal—is taboo, even in contemporary American life. His mother locks him out. That’s the first real time we get that being a vampire (being out as a vampire), for Simon, has a price.

Holly: The person we know best in the books who has experienced both the boon and burden of immortality is Magnus. And because the Infernal Devices is set more than a hundred years earlier than the Mortal Instruments, we get to see how Magnus has changed over time. Immortality isn’t a burden just for him, it’s a burden on the people close to him. As his relationship with Alec grows, Alec has to figure out what it means to be with someone who has lived so much before him and will live so long after he’s gone.

Kelly: For the writer, an immortal character offers a chance to tell a lot of different stories, to rework the character in interesting ways. Magnus’ arc as an immortal is interesting to me for two reasons. One, his love life follows a pretty classic vampire character arc: He’s loved and lost and loved and lost again. But because of his apparent physical age, he’s attractive to—and attracted by—young adults like Alec. Sound familiar?

Second, he’s bisexual. (Oh, and he’s Asian. That’s a lot of intersectionality going on!) In terms of audience reaction, his sexual preferences seem much more notable than the fact that he’s immortal. That’s pretty new. There aren’t a lot of bisexual immortals in popular fiction.

Holly: Would you consider Anne Rice’s Lestat bisexual? He didn’t really have sex with anyone, just engaged in a lot of biting.

Kelly: Well, yes, but he’s not bisexually active in the books, at least not on the page, not explicitly. There’s a very good reason why it’s appropriate that he was played by Tom Cruise.

Holly: The thing that fascinates me about Magnus is that he appears to be the most human seeming of the Downworlders we meet, because he’s so friendly and up on popular culture. He buys scarves at the Gap! Raphael and Camille are more menacing and seem more inhuman.

But when Magnus thinks about humanity, even as someone with a human parent and who once had a human life, he sees himself as outside of it. For example, “Magnus had always found humans more beautiful than any other creatures alive on the earth, and had often wondered why. Only a few years before dissolution, Camille had said. But it was mortality that made them what they were: the flame that blazed brighter for its flickering. Death is the mother of beauty, as the poet said. He wondered if the Angel had ever considered making his human servants, the Nephilim, immortal. But no, for all their strength, they fell as humans had always fallen in battle through all the ages of the world.” These are the thoughts of a being who might look human, who might try to act human, but who is essentially other.

Kelly: We all want what we can’t have. Magnus immerses himself in humanity to keep himself human. Talking about this helps me understand better why, in books, immortals—especially vampires—like to hang around with young adults. If your baseline condition is one of stasis, you might need regular jolts of chaos, change, extremes. Teenagers are to the immortal as cups of coffee are to the writer, except that the problem for writers is that they have deadlines and the problem for immortals is that they don’t.

Holly: So teenagers are reinvigorating? Kelly:…

Holly: Well, reinvigorating to drink anyway.

Kelly: I always wanted to ask Cassie if Magnus was inspired, at all, by Diana Wynne Jones’ wizards Howl and Chrestomanci. Cassie?

Cassie: By Howl, yes. Not so much by Chrestomanci. I always loved that scene in Howl’s Moving Castle where Howl dyes his hair blue. I wanted to write wizards that weren’t old and gray like Dumbledore. Everybody pictures wise, ancient, beardy wizards. I wanted to write a wizard who was young, a New York raver, a party boy.

Holly: It’s interesting that an immortal person who appears very young is much more eerie and alien seeming than an aged character like Gandalf living forever.

Kelly: Most cultures have myths about figures like Magnus, though. Fairies, gods who appear as youths to court mortals, and of course lots of scary children who aren’t what they seem. The child—or the young adult—in fiction represents potentiality, for good or evil. And that’s a big part of all of Cassie’s books— young adults, like Clary, who discover that they are much more powerful than they thought they were and that the world is much stranger. Or else young adults who, like Simon, get changed into something they never expected to become—maybe never even knew it was possible to be. Of course, that’s a big part of young adult literature, period. It’s a literature of discovery and change. You, the protagonist, have to discover the world. And at the same time you have to discover what you are that you didn’t know was possible. You are changed. You change the world. The literature of the fantastic enlarges all of these possibilities.

You know what I find really interesting? Not that there are immortals in Cassie’s books, but that, given the possibility of immortality, her Shadowhunters are so very, very mortal. The blood of the angel Raziel gifts Shadowhunters with many things but not immortality. In fact, as Will Herondale says in Clockwork Angel, “It’s not a long life, killing demons. One tends to die young, and then they burn your body.”

Holly: So that the risk of dying young, being a Shadowhunter, being mortal, gets associated with divinity, with the way that things should be. And on the other hand, immortality is linked to the infernal. Only Downworlders get that gift—warlocks, faeries, and vampires—so it must be a by-product of their demon blood. Werewolves are the only Downworlders to miss out on the immortality boat. So doesn’t that imply that immortality is tainted in some way, more burden than boon?

Kelly: Well, it’s always seemed to me that werewolves are the most like us: the most human of monsters. They’re inside us; you’re always a vampire, whereas you become a werewolf once a month. And they’re messy in a way that humans are messy: creatures of appetite, who suffer and die like us.

But yes, immortality comes with several pages of fine print. You stay the same, and everything else changes. Maybe it changes so much that there’s no place for you any longer, no place that you recognize or that recognizes you. Or, more important, no one. We haven’t really talked about how immortality works in Cassie’s romances, that tension between the immortal and his or her mortal lover.

Holly: Love is, traditionally, forever and ever. That’s what we say to one another, what we promise—forever. It’s a romantic ideal, but love would be way different if forever really meant forever. Can two people stand each other for that long? Can one person really have a single love that means more than any other over the stretch of decades and centuries? Is that a crazy way to think about love?

Kelly: Cassie’s books are, in large part, about people who find real love. True love. But every love story is a tragedy, even when you add immortals. Either you’re immortal and your lover isn’t. (Woe.) Or you’re both immortals, and after the first forty or fifty or five hundred years, the bloom is off the immortal rose. (More woe.) The immortals in Cassie’s books don’t fare well together.

Holly: We really see that with Magnus and Camille. She says to Magnus in Clockwork Prince, “You expect me to have the morals of some mundane when I am not human, and neither are you.” She believes that love between immortals should be fundamentally different— that rules about fidelity, for example, shouldn’t apply. On the other hand, I have always thought that there was something about Camille that seemed more essentially human than Magnus. She’s petty in a way that he isn’t—jealous of his having Alec in exactly the way she criticized him for being jealous a hundred years earlier—and she has a way of showing off that seems to be about impressing just the sort of people she claims not to care about.

Kelly: Apparently immortality is no cure for hypocrisy or insecurity. Or humanity. So maybe that’s how Camille manages her immortality. Magnus manages his immortality by flooding himself with new experiences and interests, by creating makeshift, mixed human and supernatural familial groups for himself in each new place and time. And yet he also seems to stay above it all. Camille, on the other hand, keeps herself occupied by manipulating power dynamics and personal status. How other people see her tells her what she is.

Holly: Yeah, sometimes I feel as though Magnus wants to be human, when he can’t help seeing humanity from a great distance, and Camille wants to be inhuman, but she doesn’t have his perspective. She’s down in the mess of life with the rest of us.

Kelly: Cassie, do you think of Magnus as a kind of author’s stand-in in the books? For saying what you want to say to your characters, about love and immortality?

Cassie: Yes. Usually. Everything he says about burning a lot more brightly if you’re mortal, I think that’s true. He gives good advice.

Kelly: Do you think of him as the linchpin for the series? I mean, he’s there in all of the books. Cassie: Not the linchpin, no. I think he could die. Like Dumbledore.

Kelly: I guess that’s why the series is called the Mortal Instruments and not the Immortal Instruments.

Holly: One of the things that we sometimes forget about immortality is that it’s not invulnerability. Death can come to all the immortals in the world of the Mortal Instruments.

Kelly: Well, there’s an argument to be made that all forms of magic—including immortality—stand in as metaphors for money. Magic, in fantasy, often works the way that money does. Magic buys you things: long life, cool stuff, access to the kinds of worlds that people without magic can’t get into. But the one thing neither money nor magic can buy is freedom from death.

Holly: This is making me think, as a highly practical matter, how once you become immortal, you’d be well served to spend a couple of years doing nothing but working and amassing cash so that you could live off the interest forever. Because your retirement problems are really different from most people’s. Those charts that tell you how much to put away per year are not going to work for you.

Kelly: Readers of this essay, take note: If you plan to live forever, make good investments. It’s like being a time traveler, where you want to make sure you’ve done your research, memorized some lottery numbers and the names of really spectacular stocks when you go back.

Holly: I do wonder where Camille’s money comes from. I mean, Magnus works. He’s the High Warlock of Brooklyn. As long as Downworlders and Shadowhunters have magical problems, he’s got a job. Cassie, where did Camille get her money from?

Cassie: I’ve decided that she had a string of lovers who bestowed many jewels on her because she is so beeyoo-tiful.

Holly: Really? Cassie: No. I figure many vampires have money from being around so long and whatnot. Remember there’s that part in Clockwork Prince where they talk about vampires leaving their money to themselves, masquerading as their own heirs? And they have big investments that pay out over time.

Kelly: And traditionally, vampires are good at getting more than blood from their prey. They can hypnotize their victims into signing over their estates, etc.

Holly: Like a sweetheart scam, but with blood. Kelly: We haven’t talked about the Seelie Queen yet. Cassie, when you wrote the Seelie Queen, what sources were you drawing on? Which Faerie Queens were inspirations?

Cassie [points to Holly Black]: Hers. Holly: Ha! The thing I find interesting about faeries in general is that they were never human and that they are essentially other. The shorthand for that in Celtic folktales is “they laugh at funerals and cry at weddings,” but it alludes to the whole separate moral system faeries operate under. And in the Mortal Instruments, the Seelie Queen is not just untouched by her immortality but untroubled by it. For her, mortality seems skeevy. It grosses her out, the way you’d be grossed out by a rotting peach on your desk.

Kelly: I can see why you’re Cassie’s source. That’s good stuff. And of course, the Seelie Queen and her court, in the Mortal Instruments, are weirdly sideways to the rest of the Downworlders.

Holly: Awww, that’s nice of you to say. And I agree about the faeries being sideways. They’ve never been human. They’re separate from the realm of demons and angels. They may have originated there, but now they are a people apart, self-contained and (changelings aside) self-reproducing. All other Downworlders continue to have to truck with humanity to survive. Vampires make more vampires by turning humans. Werewolves probably can breed more werewolves but mostly seem to make more through infection. And as far as we know, warlocks can’t reproduce at all.

Kelly: Humans and faeries, in fact, appear to be somewhat allergic to each other. Like you said, when the Seelie Queen looks at Jace and the other Shadowhunters, she sees not young men in their prime but their decay and their deaths. She doesn’t get it. She says, “You are mortal; you age; you die…If that is not hell, pray tell me, what is?”

Holly: Well, forever for her isn’t something to hope for or dread or dream about. It’s a given. Kelly: I’m guessing that complicates her love life as well. In some way that we mortals probably can’t quite comprehend. Whatever it is, I’m guessing it works for her. (I keep coming back to how immortality and love intersect.) Cassie, what do you think?