Linda Danvers/Kara Zor-El's stressful routine of dealing with bullying co-workers and her lousy boss Geoff Anderson at her work as a photographer at San Francisco station KFS-TV gets disrupted when a mysterious Amazon called Nightflame, wielding a sword with terrible energy powers appears in San Francisco through a portal, raises havoc, and demands that Supergirl be brought to her.
After tearing down and burning down a chunk of the city, Nightflame locates the Girl of Steel at KSF-TV. Supergirl tries to fight her, but Nightflame quickly and easily knocks her out, separates her spirit from her body, and flies off.
When Supergirl awakens, she finds herself depowered and trapped in a strange hellish world, beset by demons and Nightflame, who reveals that world is the Innerverse, a psychical micro-cosmos created by Linda's inner darkness. However that world is dying, and Nightflame has a plan to fix that: take over Supergirl's body.
Demon Spawn provides examples of:
- Absurd Cutting Power: Nightflame's flaming sword is imbued with magic which allows it slice through anything: cars, buildings, dimensional barriers...
- Absurdly Sharp Blade: Nightflame's magic sword can cut anything, including dimensional barriers.
- Alien Sky: In the Innerverse, the sky is a dark-violet void.
- Always Second Best: 'Nasty' is a better photographer than Linda. Linda hates to admit it, but she is aware of the fact. Of course, she would have an easier time admitting it if Nasty didn't rub it in the whole time.
- Another Dimension: The Innerverse is a dimension created by Supergirl's dark side which exists inside her mind.
- Anti-Villain: Technically Nightflame wants to save her world and its denizens... by destroying Supergirl's soul, taking over her body and doing evil things.
- Aura Vision: Nightflame can sense Linda. Supergirl's aura guides her towards her.
- Awful Truth: Nightflame reveals that the Innerverse and its demons are Kara's own evil. As Linda faces a cyclopean, wrinkled demon, she doesn't want to believe it.Nightflame: Peer into your soul, Supergirl, and see what you have never faced... your own evil!
Supergirl: Wha—? This... This thing exists within my own body! No, it can't be! Nothing as evil as all this could be part of me!
Nightflame: Yes, it is part of you... and of all mortals.
- Badass Cape: Supergirl's cape.
- Battle in the Center of the Mind: Supergirl and Nightflame fight into Supergirl's mind an illusory, hellish psychic landscape called Innerverse that represents Supergirl's dark side. Nightflame tries to drain Supergirl's life-force and powers, but Supergirl is helped from "outside" by Geoff, who helps her fight off her mind-rape until she breaks Nightflame's spell and frees herself.Finally, the drama within her reaches a fever pitch... thoughts are pushed and pulled back and forth within her mind at ever-increasing speed... and, at last, the landscape can take no more and erupts with fantastic fury...
- Black Cloak: Nightflame wears a black-and-red cloak.
- Black Mage: Nightflame and her demons.
- Blatant Lies: When her boss Geoff and her rival Nasty inquire what happened and what was that loud boom coming from her office, Linda replies "Oh, nothing!"
- Blue Is Heroic: Linda wears a blue shirt.
- Brought Down to Normal: Linda gets stripped from her powers when she is brought to the Innerverse. She feels even weaker than an ordinary human.
- The Bully: Nasthalthia "Nasty" Luthor works as a photographer in KSF-TV news, and constantly disparages Linda and picks on her.Linda: Perhaps you're right! Nasty is a rather good news photographer! (thinking) Though I hate to admit it!
Nasty: Rather good? Compared to you, I'm the whole Galaxy Broadcasting Service News staff rolled into one person!
Linda: Come off it, big mouth! I'm nearly as good a photog as you!
Nasty: Perhaps! But nobody really knows, since you're never around when a big story breaks!
- Bullying a Dragon: 'Nasty' cannot prove it, but she knows Linda Danvers is Supergirl. The short-tempered hero who can move planets. And still Nasty picks on Linda, disparages her and tries to get her fired.
- The Cape: Supergirl is a real hero, not because she is perfect -she is not- but because of her powers allowed her to do anything, and she chose to be a good person.And part of her goodness is being torn away with it... for it was her heritage, her superiority over ordinary mortals, that forged her to make the ultimate decision to use her powers for good rather than for evil...
- Collapsing Lair: Once Supergirl defeats Nightflame and her minions, the Innerverse collapses. Justified, since it was Supergirl's dark side's psychic manifestation, so it was destroyed when Supergirl beat her inner demons.
- Crucified Hero Shot: Kara assumes this position when Nightflame places her in an unholy light pentagram.
- Curse Cut Short: In Adventure Comics #421, Pre-Crisis Linda Danvers grumbles (after putting up with her overbearing, self-serving, mean-spirited rival and co-worker Nasthalthia 'Nasty' Luthor):Supergirl: That lousy "Nasty" — She's out to get me fired — That rotten, under-handed stupid w...
- Cyclops: One of the Nightflame's flunkies is a short, wrinkled, bald, purple-skinned cyclops dressed in red robes. He attempts to suck out Supergirl's powers and life essence and transfer them to Nightflame.
- Dark World: Supergirl is kdinapped and brought to the Innerverse, a world which exists inside her own mind, born from her dark side, and inhabited by hordes of demons and monsters. The sky is a featureless, violet void, the trees are dried and leafless, the land is barren and rotten, and the water is poisonous.Nightflame: This is Innerverse! It exists upon one of the atoms that make up your own brain! It is a world of sorcery! A dying world... dying because your goodness is eating away at the evil this microcosm is composed of!
- Death Seeker: Nightflame is actually Linda's dying wish embodiment.
- Demonic Possession: Nightflame steals Supergirl's soul in order to drain her life-force and take over her body.
- Enemy Within: Nightflame's plan consisted on bringing Linda's soul to the Innerverse and stealing her body and her powers.
- Enemy Without: Nightflame, a sword-wielding witch who was a manifestation of her dark side — specifically her death wish — who left Supergirl's mind and entered the physical world to fight her and capture her.
- Everything's Better with Spinning: Supergirl spuns around at Super Speed to create a whirlwind and put out the fire burning a building down.
- Evil Is Burning Hot: Nightflame has control over fire. She burns down streets and whole buildings as she looks for Supergirl.
- Evil Is Hammy: Nightflame is verbose.Nightflame: Nay! Your chrome-plated chariot does not frighten me! Now you shall know of the power of Nightflame! And of my flame-sword!
- Fight Off the Kryptonite: Supergirl loses her powers when she is brought to the Innerverse. However she fights off Nightflame magic as hard as she can.
- Fire-Breathing Weapon: Nightflame has a sword that shoots fire like a flamethrower.
- Flaming Sword: Nightflame◊ wields a long, broad, double-edged flaming sword.
- Green and Mean: Nightflame◊ dresses a full-body, tight, green suit. She is a Flaming Sword-wielding warrior and sorceress. Even her sword's flames are green.
- Green-Eyed Monster: 'Nasty' is glaring and fuming when Linda and Geoff kiss.
- Hair Decorations: Linda wears a white hair-band.
- Heroes Want Redheads: Linda likes red-haired Geoff.
- Hoist by His Own Petard: Nightflame summoned a floating pentagram in order to drain Linda's powers and life-force. During her final bout, Supergirl grabs Nightflame and tosses her in the floating sign. Nightflames body dissolves instantly.
- Hoist Hero over Head: Supergirl does this when Nightflame lunges at her: Kara dodges her strike, grabs her and throws her overhead.
- Hot Blade: Nightflame can heat up her huge magic sword.
- Hot-Blooded: Linda is passionate and temperamental. Definitely more temperamental than her cousin. After 'Nasty' picks on her, she goes to her office to cool off... by swearing and punching a wall.
- Iconic Outfit: Supergirl's "short-pants" seventies costume.
- "I Know You're in There Somewhere" Fight: As Supergirl tried to fight Nightflame's magic inside her mind, Geoff cradled her lifeless body, trying to wake her up.Underlying: What... What's this? Her helper is far stronger than I thought! Attuned to her thoughts! He's locked into certain parts of her mind! I can't dispel him!
Supergirl: Whoever you are, keep it up! I can feel your influence growing stronger and stronger! Breaking through all the pain and torment!
- In the Back: Nightflame attacks Supergirl from back, striking the heroine's temple with the flat of her magical blade.
- Killed Off for Real: Nightflame never was seen again after Supergirl eradicated her.
- Kryptonite Factor: Nightflame is a sorcerer. Kara is vulnerable to magic because it bypasses her natural invulnerability.
- Lady of Black Magic: Nightflame subverts the type. Although she is a powerful mage, she is also a formidable physical fighter and swordswoman.
- The Legions of Hell: The Innerverse is inhabited by legions of misshapen demon-gnomes.
- Life Energy: Nightflame tried to suck Linda's life-force out of her.
- Loves My Alter Ego: Geoff loves Supergirl but he is not interested in Linda romantically.
- Mass "Oh, Crap!": A group of random bystanders has this reaction after seeing Nightflame blowing a street up and striding towards them.
- Milking the Giant Cow: Nightflame gestures her left arm skywards while she demands to know Supergirl's location.
- Mindlink Mates: Downplayed. There was not telepathy involved per se exactly, but Supergirl and Geoff's minds were bonded somehow, and that bond gave strength to Supergirl to break free.Supergirl: It was someone entering my mind, letting his thoughts flow in with mine that allowed my will to live to ultimately win!
- Mind Rape: Nightflame and her minions do this to Supergirl, stealing her soul and trying to drain her life-force and her powers in a psychic hell as tearing away a part of her mind.
- Nigh-Invulnerability: Supergirl is nearly completely invulnerable. She withstands flames and crashing into walls.
- Oh, Crap!: Out of frustration, Linda hits a wall and almost demolishes it. Then she heard people coming and got this reaction.Voices: What was THAT? Sounded like a plane crashing into the building!
- Ominous Opera Cape: Nightflame wears a long, flowing, black cape.
- Our Hero Is Dead: After Nightflame steals Supergirl's soul, Geoff and Nasty examine her motionless body and tell she's dead.
- Pedestrian Crushes Car: As soon as Nightflame steps into the physical world, a car moves in on her, and the woman crushes it.
- Percussive Therapy: After having an argument with 'Nasty', Linda shuts herself in her office and she is so angry that she punches a wall.Linda: That lousy Nasty! She's out to get me fired! That rotten, under-handed stupid w... I'd like punch... OOOPS!
- Person of Mass Destruction: Supergirl is her Earth-One, planet-mover incarnation. In addition to her, Nightflame smashed a car, wrecked a street, and blew up and burned down several buildings in only two pages.
- Playing with Fire: Nightflame can channel tongues of flames through of her blade. She is more than capable of bringing down a building with her pyrokinesis.
- Pocket Dimension: The Innerverse is a pocket dimension created by Supergirl's dark side which exists inside her mind and is a kind of hell inhabited by demonic monsters.
- Portal Door: Nightflame opens a dimensional rift to travel from her universe to the real world.Suddenly, it appears — hanging in mid-air... Here, on a street in San Francisco... Shimmering, crackling and growing... a crack, a rip in the very fabric of the universe! And out of it comes a figure... humanoid, yet huge... an Amazon... brandishing a fiery sword!
- Power Floats: Nightflame makes Supergirl float while she cast her spell.
- Power Glows: Nightflame's sword glows when she uses her powers, blasts flames or casts spells.
- Powers as Programs: Nightflame intends to transfer Supergirl's powers to herself.
- Primary-Color Champion: Linda wears blue and red in contrast to Nightflame's green outfit.
- Red Is Heroic: Supergirl wears red cape, short-pants and ballerina shoes.
- The Rival: Linda and 'Nasty' work as junior reporters and photographers for KSF-TV and are rivals. Linda is willing to admit out loud that Nasty is a better photographer, but Nasty is always belittling Linda as selling herself so their boss fires Linda.
- Scene Cover: The issue's cover features Supergirl being seized by demons as villain Nightflame holds a flaming sword above her. That scene happens, although slightly tweaked.
- Secondary Color Nemesis: Nightflame sports a green tight outfit.
- Secret Chaser: 'Nasty' tries to out Supergirl's Secret Identity while the Kryptonian heroine is trying to get her out of a burning building.
- Small, Secluded World: The Innerverse is a secluded pocket dimension created by Supergirl's dark side which exists inside her mind and outside of the physical world.
- Smooch of Victory: Supergirl kisses Geoff after he saves her.
- Smug Snake: "Nasty" is a supercilious bully who is permanently trying to out Linda or get her fired, but she is too arrogant and not clever enough to be something else than a thorn on Linda's side. When Supergirl is rescuing her, she takes advantage of her closeness to tug at her hair, thinking Supergirl wears a wig... and it is Linda the one who wears a wig.
- Soul Power: Nightflame can remove souls from their bodies. She pulls Kara's soul out from her body and makes off with her back to the Innerverse.
- Standalone Episode: The story can stand on its own.
- Statuesque Stunner: Nightflame is tall. Supergirl is occasionally portrayed as 6'00'', and she is about two heads shorter than Nightflame.
- Superhero Sobriquets: Supergirl is called "Blonde Blockbuster", "Princess of Power" and "Maid of Might" at several points.
- Super Senses: Linda's Kryptonian senses can see and hear anything.
- Super Speed: Linda's lightning speed allows her put out a fire by spinning quickly until she forms a whirlwind, and dodge Nightflame's strikes.But the Maid of Might moves with lightning speed...
- Super Strength: After arguing with 'Nasty', Linda punches a wall out of anger and frustration. She accidentally cracked the wall and moved a cabinet to cover up the hole. Meanwhile, her co-workers wondered whether a plane crashed into the building, so loud resounded her punch.
- Super Toughness: Supergirl endures the heat of a burning building and flies through a wall without getting hurt.
- Taking You with Me: Once her plan has failed, Nightflame's world is dying and her too. So she attempts to destroy Supergirl to kill them both.Nightflame: I have failed to gain your powers, my world is at an end! There, I do not wish to live! By destroying you... I destroy myself!
- Teleportation: Nightflame is able to cast magical dimensional portals.
- There Was a Door: Supergirl burst through a wall of the KSF-TV building wall to get to Nightflame.
- Two-Person Love Triangle: Linda/Kara likes her boss Geoff. Geoff likes Supergirl but he is not interested in Linda.
- Ungrateful Bastard: 'Nasty' attempts to out Supergirl as Supergirl is saving her life.
- What the Hell, Hero?: Nightflame shouts at Supergirl that she is destroying the Innerverse and killing its denizens. It doesn't work given that the Innerverse is:Nightflame: This is Innerverse! It exists upon one of the atoms that make up your own brain! It is a world of sorcery! A dying world... dying because your goodness is eating away at the evil this microcosm is composed of! [...] Look! Look at what you've done! Look at all the decay, all the destruction! Our people are dying — They are being dragged down by a planet that no longer supports them!
- Who Wears Short Shorts?: Linda wears her red "hot-pants" Supergirl outfit.
- X-Ray Vision: 'Nasty' and Geoff got knocked out during Nightflame's initial attack. Supergirl checked that they weren't seriously hurt using her X-Ray vision.
- Your Magic's No Good Here: Kara's superpowers don't work in the Innerverse.
- Your Soul Is Mine: Nightflame stole Supergirl's soul while she was alive.