I don't own Supergirl. DC Comics owns the character, and the TV series is owned by Warner Bros and the CW.

Also, Seigel and Shuster families? Yeah, okay, Superman and related works created by Jerry Seigel and Joe Shuster.

Bases covered? Okay, great.

So…

Now you guys know what happens when you mix anemia with binge-watching of Supergirl's second season.

Okay, in all seriousness, let's get some housekeeping out of the way. First, I'm fine now. Blood counts are up, I'm taking iron supplements and adjusting my diet, etc. This idea just came to me when I was sick this summer and it wouldn't leave, so I started putting it down and couldn't really stop.

Second, a pair of characters show up periodically, one more than the other. They are based on a pair of characters from the Castlevania franchise, but I just borrowed the names and some details. Other details are radically different enough that I feel like can safely call them mine, hence why Castlevania isn't in the disclaimer.

(For one thing, my Shanoa is Irish…)

Third, the elephant in the room: Mon-El. As you might have guessed from the summary, this AU does not include him. In fact, it goes out of its way to remove him from the equation altogether. There is a very good reason for this:

I don't like him.

As a character, he never really gelled with me until near the end, and I spent most of the season grinding my teeth at his antics. When the romantic angle was pushed, it got even worse. He lied to Kara from day one (which, no Music Meister, she is completely in the right for being mad about), he repeatedly disrespected her in several ways, and I never bought the chemistry between them. I kept thinking to myself 'She's got more chemistry with Lena Luthor, and they're not even a couple!' Imagine my surprise when I look up fan works and find I'm not the only one who had that particular thought.

Fourth, bit of a slow burn as far as Kara and Lena. Kara's going to have some issues to work out first.

Now, with all the out of the way, have a Merry Christmas and enjoy this tale of a sunny superhero being turned into a menacing creature of shadow!

…

Fa-la-la-la-la, La-la-la-la…

Supergirl: Blood Ties

Chapter 1

Infection

Kara sighed as she looked at the comatose body. The whole affair was a mystery. The pod had looked Kryptonian at first glance, but closer inspection revealed it to be a clever mimicry. The passenger within looked human, down to his internal organs, but everything else screamed alien. But what it was, they didn't know. None of the DEO records had this.

The alien was pale, with thin black hair and a hooked nose. Something about the overall aesthetic seemed familiar, but Kara couldn't put her finger on it.

"I'm not even sure you can hear me. I hope that little adventure I told was entertaining regardless."

A wistful smile graced her face.

"It just felt so good. Me and him, working together and being heroes. I would certainly like more Super team-ups in the future. I love Clark, but…he's just not around very much. It would be nice to have a relationship with more to it than texting. Granted, the texts would always be a highlight of my days, but still…"

She leaned back, lost in thought.

"I wonder if I can pick his brain for reporter stuff. He's been at that for so long, I could probably use some tips."

So lost in thought was she, that she missed the twitching of the alien at first. It was only when the heart rate monitor picked up that she noticed.

"Oh, Rao! You're waking up!"

She leaned forward to check him over when his eyes snapped open. Kara was taken aback at them, a blood-red glow emanating from their depths and filling the whole eye.

And then the alien reared up and latched onto Kara with a hiss. With unexpected strength, it pulled her closer, and then Kara felt a spasm of pain from her neck.

Then she began to feel very weak…

oOo

"Guys, you want to see this," Winn called, running up to Alex and J'onn with a tablet in hand.

"Agent Schott," J'onn said by way of greeting, "What's the problem?"

"Okay, so, to familiarize myself with the database, I decided to look up some sci-fi icons to see if there were any real equivalents. I'm a geek, sue me. So just for shiggles, I looked up vampires, and got a hit."

He turned the tablet around, revealing a file.

"This file is apparently so old, the entirety is scanned paper documents, so I doubt a lot of people have ever seen it. Hemovores that came to Earth centuries ago, nowadays keep to themselves, any sightings slipping into myth and legend-"

"Fairly common with older races who come to Earth," J'onn said, "Sasquatch for example. What's your point?"

"Well see—wait, Bigfoot's real?"

"Winn, the point?" Alex pushed.

"Right, right. So, I was reading though it, and some of the characteristics look suspiciously like the guest we have in the med bay. And according to the file, really old school vampires were a lot more aggressive than the guys we have on Earth now."

Alex skimmed the information on the tablet before nodding.

"Right, I'll go to the med bay and strap down our guest, just in case."

Alex gave the tablet back and speed-walked to the med bay. Upon entering, she froze for a milli-second before instincts kicked in and she drew her gun.

"Get the hell away from her!" she screamed, firing three rounds into the back of the creature with its teeth on her little sister's neck.

The vampire screeched and dropped Kara, then turned to Alex, looking more ticked off than hurt. But Alex fired a few more shots, one of which hit the creature in the neck and staggered it.

Then there was a blur of red light, and the vampire had been punched to the other side of the room.

The vampire quickly regained its wind, but upon seeing an angry Martian standing there, it decided that discretion was the better part of valor. It ran sideways, jumping out of the nearest window in a shatter of glass and escaping into the night.

With the danger gone, Alex rushed to Kara's side, suppressing her fear at the gush of blood on her sister's neck. A cursory inspection showed a bad wound.

"J'onn, help me get her to the sun lamps!"

The Martian complied before pressing gauze to the wounds in an effort to stem the bleeding. However, the second the lights were turned on, Kara began to scream and write in pain. Alex immediately turned the lights off, staring in shock at the curls of smoke rising from pinkened skin.

"What the hell? It hurts her now?"

oOo

It took a while to get Kara stable, and then tests were run. What was found was extremely worrying.

Alex had taken a blood sample and looked at it under a microscope, finding some foreign bodies in Kara's blood. The foreign bodies were assimilating her cells, but in many cases, the process led to the cells being destroyed.

It was actually Winn who hit on the answer.

"Vampires burn in the sun, right? Their bodies can't take the light. Well, if Kara's turning into a vampire, how does that gel considering she's powered by sunlight?"

"Great H'ronmeer," J'onn gasped, "Her body must be ripping itself apart."

"So what do we do?" Alex asking, taking note of Kara's elevated heart rate, "Those sedatives won't work for long, and I'm not about to watch my sister die!"

"I found some contact information in the vampire file," Winn said, "A specialist, maybe?"

"Make the call, and tell them it's a matter of life and death," J'onn ordered, and Winn left to do just that.

J'onn then joined Alex at Kara's bedside. The blonde was sleeping thanks to the sedatives, but she twitched and moaned at random times, her face a grimace.

"What if this doesn't work?" Alex asked, taking a cool cloth to her sister's sweaty head.

"It has to."

oOo

By sheer luck, the contacts had been wrapping up a job in Oregon, and were able to rush south to National City.

Two hours later, two people arrived at DEO Headquarters and were swiftly brought to the med bay.

"Director…Jones, was it?" the man said, leaning forward to shake J'onn's hand, "My name is Adrian Tepes. This is my wife, Shanoa. I believe we're here to consult."

Adrian was a reedy man, but J'onn noted that his grip was strong. He wore a nice brown suit, looking more like a business man than an expert on vampires. His face, however, told a different story. His skin was pale, his eyes were sunken and dark, and his shocking white hair was pulled back into a long ponytail. He looked fairly haunted, but his mannerisms and posture didn't seem to reflect that. He spoke in a measured fashion, and an Eastern European accent could be heard if you strained your ears enough.

Shanoa was almost his opposite. Her curves and skin-tone were much healthier looking. Her long black hair shined in the light. Her steps were a touch jauntier, and she possessed a serene smile and light gray eyes. She wore a dress of deep blue, accentuated by a metal belt made of interlocking Celtic knots. Alex noted that when her sleeve shifted, she could see black lines on her arm, likely tattoos.

J'onn, Alex, and Winn explained what happened, and while Shanoa looked over Kara, Adrian asked more questions about Kara's physiology, "to better understand why her body is reacting the way it is."

After a while, Adrian and Shanoa stepped to the side and exchanged hushed tones.

"Right, we think we've got a solution," Shanoa said, a light Irish lit on her tongue.

"And?" asked Alex.

"Your friend Winslow's hypothesis was correct," Adrian began, "The vampire transformation leaves her vulnerable to sunlight, the same force that her body uses for power. She is at war with herself, and since neither force can be stopped, the only thing to do is add something that can resolve the conflict. I can augment her new vampiric nature with another bloodline, one more resistant to the sun's light."

"What do you mean augment with another bloodline?"

And then the eyes of their visitors glowed a menacing red, and fangs extended from their mouths.

Winn shrieked and fell backward in his chair. J'onn nearly morphed into his Martian form. Alex's hand went to her gun.

"There's no need for that," Shanoa said, gesturing toward the holstered weapon, "We're only here to help."

"How is turning my sister into a vampire supposed to help her?"

"There is no force on Heaven or Earth than can stop her transformation," Adrian intoned, "But if it continues unchecked, she will die. If she is to live, it has to be as a part of our bloodline. There is no other way."

The three agents looked at each other, then back at the vampires.

"This will save her life," Shanoa said softly.

Alex took a sharp breath.

"Okay, do it."

The two vampires nodded and put their fangs and glow away. But instead of going over to Kara, they instead went to another table and began to draw on a pad of paper. A circle with several symbols formed, and the two muttered to each other.

"Mist of course, that's really fun," Shanoa said.

"Bat form, standard. Hearing?" asked Adrian.

"I think she has enough, but there might be a minor uptick regardless. How about some sorcery?"

"You just want another student."

"Guilty."

"What are you going on about?" asked Alex.

"Due to the way I'm doing this, one part turning and one part blood adoption, I can pick a few advanced traits to pass. A few will anyway, but this will ensure it," Adrian explained

"Before you ask, no, we can't lessen the thirst for blood. Only time and experience can do that," added Shanoa before turning back to her husband, "Hey, isn't that-"

"Yes."

"I wasn't aware that could be passed like this."

"It usually passes on its own, but I want to be sure. She's in for a rough time, anything we can do to lessen her pain is the right thing to do."

"What trait?" asked Winn.

"Later," Adrian said in a tone that brokered no argument.

They soon finished, and Shanoa waved a glowing hand over the completed circle. A match made of reddish light appeared above the paper. With a flick of her wrist, it enlarged and covered the area around Kara's bed.

"Glyph-based magic is my specialty," she explained as Adrian entered the circle, a dagger now in his hand.

"Because of course the vampires are magic," Winn snarked.

"Now, to be fair, the original vampires came from one magic rich planet to another…if a different type of magic."

Adrian cleared his throat for silence. With a growl, his fangs extended. He chanted in an ancient tongue as he cut open his hand. Blood pooled in his palm and he tipped it into Kara's mouth, never ceasing his chant. The room took on a chill as the circle glowed with haunting red light.

Finally, he stopped, and the circle flashed once before fading.

"It is done. We just need to wait as her body accepts the changes."

It actually already looked like it was working. Kara was no longer twitching, and her grimace seemed to have lessened a bit.

Since they had time, Adrian and Shanoa decided to give the three a crash course in vampire history.

"It seems prudent, considering," Shanoa said, gesturing toward Kara.

As the DEO files had stated, the original vampires were indeed aliens. They had come from a world low on sunlight, but rich in magic. The reasons for why some vampires had abandoned their world, or why they chose Earth, had been lost to time, but Earth had proven to be an interesting choice. While a number of vampire bloodlines will burn in the light of day, many had built up a resistance to it, with the Tepes bloodline being an extremely resistant example.

"She will likely have to watch how much sun she intakes, but otherwise, she should have few issues," Adrian said.

"Why are some vampires so resistant?" asked Alex.

"Evolution, sped up by magic," Shanoa said, "Earth's magical field is very different from the original planet's, so adaptations tend to have a skewed timescales. But it can be fairly random, which is why you have all those conflicting stories about vampire strengths and weaknesses."

"What's Kara in for?" asked Winn.

"Not much physical augmentation, she was already a level above average vampires. Maybe some hearing increase, I'm not sure. She can turn into mist or a bat. Weaknesses, I'd say she'd need to watch out for silver, but it will more likely be like a severe skin allergy and less like bursting into flames on contact, although I imagine she will feel burning sensations. I do. Garlic, that'll be trouble. Then there's magic. I'm guessing she was already vulnerable to it, that's how the vampire managed to bite her in the first place. That's probably not getting better, but the good news is, our bloodline is very gifted in magic. I'll be able to teach Kara everything she knows about how to protect herself."

"That's good," J'onn said, "What concerns me now is the vampire who started this. He got away."

"Indeed," Adrian said, "Vampires on Earth now are different thanks to time and environmental changes. The original strain, however, is very raw and unrefined. It will unlikely be able to peacefully exist in the modern day. Fantastic. I have enough issues with modern rouges."

"Maybe we'll get lucky and he accidentally fries himself in the sunlight," Winn said.

Everyone stared at him.

"Well, someone has to keep a positive outlook."

"So, modern vampires?" J'onn asked.

"We tend to keep to ourselves, police ourselves, and try not to kill too many people," Adrian said, "Complete non-death is impossible, we are predators by nature, but we try to cover ourselves as best as possible. My wife and I go around to various vampire communities and trouble shoot. Help newbloods, prevent or cover up accidents, things like that. There is actually a small community here in National City."

"Really," Alex asks, eyebrows raised in surprised, "I had no idea."

"A testament to our ability to hide."

"Will you be able to help Kara adapt?"

"He can't, but I can," Shanoa said, "Adrian is a very important figure in vampire communities, and not just as a troubleshooter. Business stretches all over, so we tend to be on the move a lot. But I plan to stay. I can help the DEO learn more about vampires, and mentor our latest newblood, teach her everything she needs to know."

"Speaking of blood…"

"Ah, knew this was going to come up. Kara will be able to subsist on donated blood, but it isn't ideal. The equivalent of eating nothing but takeout and easy-cook meals. As a human body needs fresh food, so will she need fresh blood on occasion. And that means feeding from a living person."

Alex opened her mouth, but Adrian cut her off.

"I know you're going to offer, and that's fine. If she paces herself, she'll be able partake of your blood when she needs it. No more than donating to a blood drive. You will be fine, and she will get what she needs. However, the first feeding is always the hardest. She will require large amounts of fresh blood, and this will likely kill whoever she feeds off, a combination of need and new instincts. I doubt she would want her sister's death on her conscience."

Alex grimaced.

"I have a hard time thinking of Kara killing in cold blood," Winn said.

"She will not have much choice, I am afraid. But I have known many of these 'white knight' types. It will be easier if the feed is an unrepentant and despicable soul. Say, a rapist?"

"That seems to be the best solution to a bad problem," J'onn said, "Alright, let's find Kara some dinner."

But their next move was cut off by a blur of red and blue zooming out the door.

They all stood there, blinking stupidly before Winn spoke up.

"She heard the tail end of that, didn't she?"

"Most likely."

"Probably."

J'onn spit out a Martian curse.

"Kara…"

oOo

"NONONONONO!"

"Kara-"

"NO!"

"Kara, please come out."

"I won't do it, Alex. I won't be a monster!"

"Kara, if you don't, you'll die," Shanoa argued.

"Supers don't kill. Supers don't kill!"

Shanoa rubbed her eyes and looked over to Alex.

"Your sister is incredibly stubborn."

"Tell me about it."

Kara had been found swiftly. She had locked herself in a private cell and curled up in a ball, crying and screaming about being a monster. Alex and Shanoa had spent the past half hour trying to calm her down, but not only had Kara somehow broken the lock and thus sealed herself inside, she was refusing to talk to either of them. She just kept ranting about how she wouldn't do it, and how Supers didn't kill.

Adrian had left to find a rapist, and J'onn and Winn had gone to make a call.

"How will we get her out?" Shanoa asked.

"Winn can probably figure a way around whatever Kara did, or we can just have J'onn bust the door down if we need to. This isn't a particularly optimized cell."

"Then why lock herself in if she could get out? She's easily stronger than your Martian."

"It's probably more psychological. The DEO hunts and imprisons rouge aliens. The aliens who would hurt people-"

"Go in cells, I see now. She must have a low opinion of herself."

"She's just in shock."

"Let's see if we can't ease it," came a voice, and Superman entered the room.

"We thought he could help, so we made a call," J'onn said, entering the room with Winn at his heels.

"I'm up to speed. Kara…Kara, it's Clark. It's cousin Kal. I'm coming in."

Superman effortlessly ripped the door from its hinges and shuffled it to the side. But when he entered the cell, Kara screeched in terror.

"Stay back! If this could affect me, it can affect you!"

"Okay, I won't come any closer," he said, bending down and gouging a line in the floor, "I won't cross this line unless you want me to."

Kara just remained curled up in the corner, staring at everyone with fear in her eyes.

"Kara, I know what happened-"

"Then you know what they want me to do. I can't, I can't, I can't."

"If you don't, you'll die, cousin."

But Kara went right back to chanting 'Supers don't kill', rocking back and forth and clutching at her ears.

Clark frowned and sat down on the floor, taking a deep breath.

"Would you like to hear a story, Kara?"

Kara stopped rocking and looked at her cousin, confused.

"Long before your friend Mr. Allen's little incursion, I've known about the multiverse. A couple of years back, I was visited by a hero from another universe, someone calling herself Superwoman. She wanted my help. Her world was being ravaged by three Kryptonian criminals. She had tried to fight, but she was the lone hero of her Earth, and she couldn't fight all three of them.

"So, while these other versions of General Zod, Ursa, and Non ran roughshod over the world, Superwoman's best friend, their world's Lex Luthor, managed to create a trans-dimensional portal. She went through to find help, and found me. I wanted to gather some more manpower, but she insisted that there was no time, so off we went.

"But when we got back, it was already too late. Zod and his minions had effectively destroyed the planet. They had boiled away the oceans, devastated the atmosphere, and killed nearly all life. We got back just in time to see him kill the other Lex."

Everyone just stared at Clark. The devastation he was talking about, the scale…it was mindboggling.

"That's…that's evil," Kara breathed.

"Now, as you can imagine, Superwoman didn't take the death of her last friend well. She went ballistic, and actually managed to kill Non herself. The two of us attacked Zod and Ursa, and eventually, the two were defeated…but the wounds that Superwoman sustained in the fight ended up killing her. And besides that, the entire planet was effectively dead.

"There was no Phantom Zone projector, no leftover ruling body to judge them for their actions of absolute genocide. There was only a Kryptonite weapon…and me."

Kara stared at him for the longest time.

"You…you mean you…"

"God have mercy on their souls," he whispered.

"No one else could have done it," J'onn said.

"You did what you had to with an impossible choice," Shanoa agreed, "I have walked the Earth for over two hundred years, and I've learned that sometimes, you have to work with the hand you're dealt, even if it is distasteful to do so."

Kara didn't answer. She just kept crying.

Adrian arrived a few minute later, carrying an unconscious body.

"I found this slime right about to do the deed."

"Hold on a minute," J'onn said, laying a hand on the man's head.

J'onn's eyes glowed for a minute, and when they stopped, he shuddered.

"It's not his first offense. He enjoys it even, and is good at covering his tracks. His mind is a sewer."

"So good riddance to bad rubbish, then," Adrian said, carrying the body into the cell and placing it on the floor.

Kara stared at it for the longest time.

"Kara," Alex said, "No one here will think any less of you for this."

Kara stared at the unconscious man some more before speaking in a small voice.

"Can we blindfold him? I don't want to see his eyes."

Adrian looked like he wanted to say something, but Clark shot him a glare and went over to the man, tearing off some of his shirt and wrapping it around his eyes.

Kara finally stood up and walked forward, picking up the body with little effort. She had been hearing it for a while. Heartbeats. The whooshing of blood through veins. She had been feeling a pull, and now it was stronger than ever.

Too strong to keep ignoring.

The call reached a crescendo, and Kara's eyes glowed a menacing red. Fangs erupted from her mouth, and with a wolf-like growl, she bit down.

The blood hitting her tongue tasted strange, like cigar smoke, but the rush if it into her belly felt so good. She began to drink greedily, soon forgetting the taste and relishing the warm liquid flowing into her mouth and down to her stomach.

She drank, and drank, and drank, until the flow reduced to a trickle. Soon, she knew, there was nothing left. The source had run dry.

Her whole body relaxed, and she dropped the bloodless corpse to the ground, panting heavily. The thump it made hitting the ground timed perfectly with the red leaving her eyes.

And as the fangs retracted into her mouth, the red in her eyes was soon replaced by tears.

"Oh Rao…"

That was all the excuse Alex needed to rush in and hug her bawling sister. Clark swiftly joined, wrapping his cape around the both of them.

"You did what you had to," he whispered to her, "You did what you had to."

"I have you, Kara," Alex whispered, "Your sister's got you. You're not alone. I've got you."

Kara just continued to cry, wailing in Kryptonian.

"Rao, forgive me for what I have done…"