A/N: Set well before the series begins, but contains a spoiler for Brotherhood episode 37/manga chapter 70, starting in the next sentence.

In the original story, Riza Hawkeye said that she felt a strong sensation of "bloodlust" whenever a homunculus was nearby, which enabled her to figure out Pride's true identity. No other character appeared to have this ability, even the alchemists, and it was never explained why. This story is my take on an explanation.

The artwork was created by the amazingly talented NoVaNoah from deviantART. Please click on it to enlarge it and see the detail, because she did a wonderful job! :)

Sensitivity

The market street was noisy and crowded this afternoon. Berthold took a deep breath, clutching his shopping basket tightly as he threaded his way through the shoppers and the racks of wares that spilled out of storefronts onto the sidewalk. The meager income he earned as a civilian alchemist did not afford much in the way of purchases, but he had managed to scrape together enough money to have a little left over after buying the week's groceries. As was his habit in such circumstances, he headed for the local bookstore to peruse its latest alchemy offerings, nodding and smiling woodenly at the few faces who took the trouble to make eye contact. His neighbors were bundled in coats and scarves against the late autumn chill, while around them the street trees stretched limbs full of dying leaves towards the gray sky.

He caught his reflection in the bookstore window and breathed in sharply. When had he become so gaunt? His shoulder-length light brown hair was stringy and unkempt, his chin sporting a few days' worth of overgrown beard. The gray wool coat he wore had a stain on the right lapel, and as an extra insult, the buttons were done up wrong. Miranda would never have let him out of the house like that, he knew. Tears filled his eyes as the familiar sense of loss overwhelmed him. It had been four months since his wife's death, and her absence was everywhere: in every corner of their home, in the very air he breathed. The only solace he found was buried in his alchemy research. He could lose himself in his study for hours, for days, and as long as he was wrapped in that protected space, he could forget his grief. He also frequently forgot to bathe, sleep or eat.

You need to do better, he ordered his disheveled reflection sternly. You need to be stronger. There was more than just his own well-being to consider.

His gaze traveled from the window to nine-year-old Riza, who had slipped here ahead of him and was quietly browsing a rack of alchemy books in front of the shop, her mop of short blonde hair and blue coat adding rare spots of color to the gray landscape. A smile touched his lips as he watched her scrutinize the book titles intently before selecting one and turning carefully through its pages. Even that brief moment of happiness was tinged with shadow. His daughter was his greatest joy, and he loved her with all his heart—but he was failing her utterly. He had always been a traditional father, working long hours to provide for the family while leaving the girl's care to his wife. Riza had been a cheerful, delightful presence he saw at mealtimes and during her alchemy lessons, but emotionally the two of them were virtual strangers. Since her mother's death, the once carefree child had grown grave and mature, already shouldering more of the household responsibilities than she should have to while he locked himself in his study. And while he hid from his own despair, she had been left to grieve alone.

She spotted him watching and held up the alchemy book she was reading (an introductory text, but still well above her age level). Smiling anew, he nodded approvingly and watched her face light up in response. Another stab of regret lanced his chest. She was a bright and studious child, and had a good grasp of such alchemy concepts as could be learned from books; but thus far she had shown no ability to perform transmutation, a skill that would have manifested long before now if she'd had any potential. Although he knew it was irrational—her mother had not been an alchemist, after all—he blamed himself for not passing down his talents. Yet another way in which he'd failed her. And her inability to share in his life's passion left yet another yawning gulf between them.

"Excuse me." A female voice, deep and faintly accented, pulled him back from the private misery of his thoughts. He turned to find a woman standing behind him. "Are you Berthold Hawkeye, the alchemist?" She was a stranger to their neighborhood, attractive, perhaps in her mid-twenties. Above full lips and unusual violet eyes, her dark hair was pulled back in a bun, and her thick black coat failed to conceal the fact that she was curvaceous, almost exaggeratedly so. Beneath the coat she wore a strangely old-fashioned long black skirt, boots, and gloves, all in black, as if she were in mourning. Something about her made him wary. "My name is Tanya," she told him. A Drachman name; perhaps the odd clothing was ethnic. "May I speak to you in private?"

He nodded, not sure how else to react, and followed uneasily as she withdrew to the other side of the street away from the crowd. She garnered a few interested looks from passers-by: admiring in the case of the men, curious in the case of the women. No one else seemed to be made uncomfortable by her presence. But this feeling that clutched at his chest…it felt almost alchemical in nature, some dark variant he had never encountered before. "Are you an alchemist?" he demanded abruptly, then inwardly chided himself for his rudeness. Whatever this sensation was, the woman had done nothing to him.

"No," she responded with surprise. "But my husband was." She reached into her pocket and produced a photograph: a blandly handsome man about her age, with brown hair and blue eyes. "He died six months ago." She ran her thumb affectionately over the well-worn photo, her eyes brimming with tears. "That's why I came to you, Master Hawkeye. I'm hoping you can help me. I've heard that you have great talent." She turned her eyes up to him, speaking softly enough that they would not be overheard. "My husband once whispered to me of a secret art that some alchemists know. One so powerful that it can bring the dead back to life. He called it human transmutation." Berthold gasped—the dangerous feeling surged even stronger—but she continued on, her voice taking on a nearly seductive purr. "If the stories I've heard of your abilities are true, then I'm sure you're powerful enough to learn this art. And I've also heard that you've recently lost your wife. If you could perform human transmutation, you could save them both—"

"Enough!" he cut her off. Her words were horrifying. "Human transmutation is forbidden for a reason! It's not possible, and those who try it risk dying or suffering horribly for the rest of their lives. Don't you think if there were any chance, I would have tried it myself?!" He had to restrain himself from shouting. Beyond her words, her very presence was so upsetting that he felt he was suffocating. For a disorienting moment her image wavered unreally before his eyes, as if she were merely a grotesque imitation of a woman—but no, that was impossible. Her provocative request must be straining his already frayed nerves. He shut his eyes tightly and took another deep breath, and when he opened them again, the illusion had passed. She was back to being an ordinary widow, if a deluded one.

"Are you so sure human transmutation is impossible?" the woman continued to prod, her eyes filling with innocent tears that no longer moved him. "A man of your talents could surely find a way. Couldn't you just try?"

"Daddy?" Riza's voice interjected before he could object again. "Are you all right?" He turned to find his daughter watching from several feet away, her expression uneasy. She must have been able to see that the woman had upset him; she had always been a perceptive child.

"Everything's fine, Riza," Berthold answered with more conviction than he felt. "Go back to the bookstore. I'll join you in few moments." The girl looked skeptical, biting her lip worriedly, but did as she was bidden.

As the alchemist turned back to the widow, he caught a flash of disdain in her eyes as she watched his daughter leave. It was an expression normally worn by certain irritable elderly neighbors, the kind who had no use for children and saw them only as a nuisance. That small revelation made her even more revolting. "I can't help you bring your husband back," he snapped at her, no longer concerned with decorum. "No one can. You're on a foolish and destructive quest, and you need to end it now." He turned his back and quickly walked away. "Don't ever contact me again," he added without looking back. She did not try to stop him.

He strode back to the bookstore, where his daughter was peering warily from behind one of the outdoor racks. "Come on, Riza," he ordered brusquely, taking the girl's hand and drawing her into a fast walk. "We're going home."

The woman watched the alchemist retreat, her face impassive. Once it was clear that he would not be coming back, she turned and strolled away toward the opposite end of the block. Though disappointed in his rejection, she wasn't surprised; viable candidates for human sacrifice were notoriously difficult to come by. Besides, they were well ahead of schedule—it would be nearly two decades before Father would need the sacrifices, and she didn't give this one good odds for making it that long.

After all, she had been studying humans for more than 200 years, and knew a man who was an ill fit for this world when she saw one. Berthold Hawkeye was the type of man who would never get over his wife's death. He would hold out for awhile, doing his best to be an upright citizen; but eventually the maelstrom inside him would pull him down, and he would lose himself to whiskey or opium or gambling, or whatever escape he used to blunt the pain of living. In five or ten years he would probably be dead.

At this end of the block the street terminated in a small public park, its few benches deserted of local residents in the chilly weather. She located her younger male companion lounging against the trunk of a large tree. His face and clothing, she noted in annoyance, exactly mirrored the photograph she carried in her pocket. "Envy," she snapped, hands on her hips, "if you walk around looking like that, you're going to spoil our little game."

He shrugged, his expression bored. "Some game," he grumbled. "You're the only one who gets to play." But his voice grew thinner and higher-pitched as he spoke, and his body glowed and shrank in stature until he had taken on the appearance of a six-year-old boy. He hopped up onto the nearest bench and walked along its length with arms outstretched, a perfect copy of a playful human child. "So, Lust," he continued, "were you successful? Is this Hawkeye chump going to be our next human sacrifice?"

Lust seated herself gracefully on the opposite end of the bench. "I merely planted the seed. The rest is up to him," she replied. Down the road leading from the market, her eyes picked out the man and girl plodding determinedly away. "I doubt this one is going to bear fruit, though. He seemed to sense something of our true nature."

"What!" Envy jumped down from the bench and stared at her. "How is that possible?"

She shrugged. "It's very rare, but not unheard of. A small number of powerful alchemists are sensitive enough to feel the dark energy that we homunculi are made of. This is the first time I've seen it personally, though."

The boy turned to eye the retreating pair. "Should we kill him, then?" he asked hopefully.

"No," Lust sighed dismissively. "That human doesn't have enough information to work out what we really are. And even if he did, he's far too busy struggling with his own demons." She waved languidly toward the man, still clutching his daughter's hand as they drew further away. Her voice held a touch of pity mingled with disgust. "Look at him. He's barely hanging on by a thread."

The alchemist and his daughter walked home in silence, Berthold still roiled by his meeting with the strange woman. Human transmutation! Was she mad?! And that bizarre, threatening feeling…he could not quite get his mind around what had just happened.

After a few minutes, Riza piped up. "Daddy, who was that lady?" she asked, her voice betraying a hint of anxiety.

"No one!" he snapped. He hadn't meant to snap. "No one important," he corrected in a gentler voice. "But if we ever see her again, you're not to speak to her. All right?"

She nodded solemnly. "I didn't like her either. She was scary," the girl volunteered.

"What?" He looked over at her in surprise. "Why do you say that, Riza?"

"I don't know." Her brow was furrowed, and she seemed to struggle to find the right words. Finally she continued, "Do you remember that night the wolf came in our yard? The lady made me think of that."

Unsettled by her words, he recalled the incident. It had happened when Riza was seven. Wolves rarely came close to their populated area, but this one had been alone and probably starving. It had killed a rabbit in their yard, and as the family had stared transfixed through the window, it had stared back at them with its torn prey hanging from its jaws, its yellow eyes flashing with pure bloodlust—That's it, he realized with a jolt. Bloodlust. The suffocating feeling he'd been unable to name.

He shuddered, certain now that the woman had been lying to him, that she was actually an alchemist who worked with some type of energy he'd never encountered before, seeking to manipulate him in pursuit of some darker purpose. Something dangerous. There were rumors and legends, of course: powerful alchemists gone bad, dabbling in forbidden arts like creating chimeras, or homunculi, or even the mythical Philosopher's Stone. Berthold had never put much stock in those stories; but today was enough to make him wonder. He tightened his grip on Riza's hand protectively. If that woman dared return to threaten them, she would face the full brunt of his own powerful alchemy, he vowed silently.

At the same time, he was filled with wonder that his daughter had sensed the exact same darkness he had. Something no one else could detect. He may not have succeeded in passing on his transmutation ability to her, but it seemed they shared something after all. The thought heartened him.

"Does that lady want to hurt us?" Riza asked, worry filling her voice and creasing her small forehead. "What if she comes back?"

"I don't think she'll bother us again," he replied truthfully. "But if she does, there's no need to worry. My alchemy is strong enough to protect us." He was genuinely confident in his abilities, but perhaps it wouldn't hurt to step up his research, just in case.

His words seemed to reassure Riza, and the tension in her face and shoulders visibly relaxed. "OK, Daddy," the girl declared. Her chin lifted bravely. "And I'll help you with your alchemy. Any way I can." She beamed up at him and he grinned back, his hand squeezing hers. He felt his heart swell in his chest, and suddenly he understood—at least for that moment—what it felt like to be a proper father.

As they continued walking down the road toward home, he fervently hoped that he could hold onto that feeling, and that he would not fail her again.