AN: Because there aren't enough Dark!Robin/Tharja fics, that's why.
Written with help of Freezingkaiju on Tumblr
Tharja ducked behind a rock as arrows flew over her head...and into the bodies of her fellow Plegians. She should probably feel something, watching dark mages and common soldiers alike, those who were supposed to be her allies, fall, but there's nothing. This battle is pointless...and they were going to lose.
The Ylissean tactician was nothing to laugh at...she was clearly good at what she did. Their forces had the Plegians backed into a corner, but with victory on the horizon, all the Plegians could do was throw themselves into death to protect the city.
Tharja grumbled to herself as she dug through her bag, trying to find something to save at least herself. She stopped when a blast of fire slammed into her cover. She pulled her cloak around her to shield herself.
"Dark gods be damned," she grumbled. "I'd rather not d-" she paused when she became aware of a presence.
Tharja looked up and found herself on the edge of the Ylissean frontline, and standing before her was the Ylissean prince, Chrom. His back was to her...no one had noticed her in the shadows. She began to get up, chanting a spell under her breath, then she paused.
Is this worth it? Sure...she could strike down Naga's holy warrior...heir to Marth. But...out of the corners of her eyes she could count at least five people who strike her down not a few moments later. Tharja let out a sigh and crossed her arm.
That sound seemed to draw Chrom's attention, because he spun around, wielding that damned blade, Falchion. It almost hurt Tharja to look at...it was far too bright. She averted her gaze and closed her eyes, expecting to be struck down by that pure blade.
"You're not fighting." Tharja blinked in confusion and looked up at Chrom, surprised to find he had lowered his blade. "Why?"
Tharja shrugged. "You've already won. To fight would be foolish. And I have no death wish."
"Don't you feel loyalty to your country?"
"Eh…" Tharja shrugged and looked away.
"Your king?"
"Eh...I mean, long live the king and all...but eh…"
"Country men?"
Tharja glanced at the nearby discarded body of a Plegian swordsman...she had known him from the camp, had a few pleasant conversations with him even, but seeing his corpse laying there, his blood staining the sand, only made her shrug and repeat the sound a fourth time. "Eh…"
"Anything?"
Tharja's shoulders fell as she sighed. This man is truly stupid. Maybe if she said it a fifth time he'd get it. But something caught her attention that made the sound die in her throat.
A white-haired woman...draped in a Grimleal cloak and wielding a lightning tome in one hand, a bronze sword in the other. She barked orders at the main line, using her sword like a conductor's baton, and this war and blood shed is her music. But when she attacked...is when she was most beautiful. As she embedded her sword into her enemies, and blasted them away with powerful lightning, something shown through the light...a powerful darkness, deeper than anything Tharja had ever seen in this plane. It...she was captivating.
Tharja twitched a little, then noticed Chrom was staring at her, waiting for a response. "I'd like to join your army," she said suddenly.
Chrom blinked in confusion. "Wait, what?"
Tharja nodded, quickly coming up with something to say to make it less suspicious. "The Plegians are going to lose, there's nothing to be done about that. I do not wish to die this day or any other."
Chrom paused, though before he could answer, he was suddenly shoved out of the way by the white haired woman. "Look out!" she cried as she blocked a blast of fire with her sword.
Tharja tore her gaze from the woman and glared past her towards one of her fellow dark mages. She wiped out an Elwind tome with a growl. "Don't interrupt," she growled before chanting under her breath...magical winds ripping the man to shreds.
Chrom nodded at the white haired woman. "Thanks, Robin."
"...Robin hmm?" Tharja mused.
The woman, Robin, didn't address Tharja at first. She instead gestured with her swords towards the cavalry and armor units to move forward. Then she pointed her sword at Tharja's chest, her tome crackling with energy. "Who is this?" she asked in a stern voice.
"My name is Tharja."
"Robin calm down, she wants to join us." Chrom reached out, putting a hand on Robin's shoulder, an attempt to calm his tactician.
"Chrom you've gotta be kidding me!" Robin snapped. "She's a Plegian, and a dark mage to boot!" She turned her attention back to Tharja. "How do we know she won't betray us."
"I would never..." Tharja said. Then she paused, confused. For some reason, the words 'My love' had come to the tip of her tongue, and she only just managed to keep herself from saying them. Her eyes fell to the woman standing before her. There was something about her...something beyond the darkness she harbored that made Tharja tremble.
"Chrom I don't like this."
Chrom nodded and smiled. "I know. But I trust what she says, I think that's what Emmeryn would want."
Robin and Tharja rolled their eyes, but said nothing. Robin simply gestured with her sword for Chrom to rejoin the fight. Chrom smiled, taking Robin's gesture as her approval. Tharja smiled at Robin, a warm feeling welling in her chest, though the smile was quickly cast aside when Robin's cold gaze returned. The tactician pressed the tip of her sword against Tharja's throat.
"Chrom may trust you, but I do not. I will be keeping my eye on you," she said darkly.
Tharja grinned and chuckled. "Fear not, dear Robin, I would never betray you."
Robin's eyes narrowed, and she pulled her blade away. "...weird mage…" she grumbled, then gestured to where a few Ylissean mages were shooting off spells. "Help them."
Tharja nodded and darted off, more than content to strike down the Plegians...especially those who came close to Robin.
The army was victorious, but the mission was a failure. Exalt Emmeryn had given her life...for nothing, or so it seemed to Tharja. She was pleading with the Plegians for them to find peace with the Ylisseans. But Tharja knew that was a pointless venture. The Grimleal, the cult who has their talons dug into Plegia, and was never going to let go...would never allow peace with those who worshiped Naga.
Tharja kept this to herself as the Ylisseans in the camp mourned. She remained on the outskirts of the camp, letting them ache and mourn without her presence. She wasn't needed...she'd be of no help to anyone. Though she noticed someone else lingering away from others...her beloved Robin.
She inched closer and watched the cloaked woman sit on the edge of camp. Robin pulled her knees up to her chest and let out a sigh. She was discontent...sad...this made Tharja strangely uncomfortable. She took a deep breath and inched closer, darting behind a nearby tent.
Robin lifted her head and glanced back. "Come out!" she ordered, that lovely darkness flaring around her once again. She didn't even seem aware of it.
Tharja took a deep breath and slipped out of hiding. "It's just me," she crooned, holding up one hand, the other clutched around her old tome.
"What do you want?" Robin asked coldly.
Tharja internally flinched at Robin's harsh tone...it felt strange, being treated so coldly by Robin, though she should be used to it. Even in Plegia she wasn't really trusted. "Nothing," Tharja said, shaking her head. "I just...don't feel comfortable being around them." She gestured back towards the heart of camp. "Why...why are you out here alone, not with the others?" Tharja tried not to let her gaze linger on the purple eyes emblazoned on Robin's sleeves.
"That's none of your concern." Robin turned back around and a strange silence fell between the two. Tharja took a deep breath and tried to inch forward once again, but the darkness lashed out at her, making her freeze in her tracks. "Why do you linger?"
"Sorry, It's just...you...you remind me of someone…" Tharja said carefully. "Someone who...who left me…"
Robin's shoulders relaxed and the darkness faded from around her. "I apologize…go back to the others."
Tharja shook her head and chuckled. "You think a proper Plegian would want anything to do with something like that?"
Robin chuckled and shook her head. "I suppose you're right…"
Tharja stepped back, bowing a little. "I suppose I'll leave you to your brooding…"
"I am not brooding."
Tharja chuckled and turned around, cradling her tome as she walked away. She slipped away to a tent on the outskirts of the camp, the tent she was assigned. It was no different from the Plegian camp and the Plegian tents. She always thought the Grimleal were lying about the Ylisseans...they weren't that different from Plegians, and this just proves it.
Tharja set her bag down on the small cot and stretched carefully, her body sore from battle. "I'll have to fight more…" she mused before sitting on the cot. "...I don't mind it actually. Huh."
She shrugged and dug through her bag, pulling out different tomes and stacking them beside the cot. Then she pulled out one of her few treasures...an old scroll her mentor gave her, and her greatest challenge. Her mentor said that this would lead to her fate. While she didn't believe in such silly things, it was a challenge all the same, and she would conquer it.
She unfurled the old scroll and set it on her lap, examining the ancient symbols that cover the parchment. She had practically memorized the old symbols that covered the parchment, she could etch out the spell circle in her sleep...but none of it meant anything to her!
Tharja stared at at the scroll and sighed for a moment before, running her fingers over symbols...when something hit her. "C-Ca...Calamity...Gate…" she muttered softly, staring at the symbol in the center of the spell circle, the symbol glowing a dark purple.
Tharja shook her head and rolled up the scroll before anything could activate. So the spell was called Calamity Gate. Tharja chuckled and grinned, that sounded deliciously awful, and she was eager to try it, but first she had to figure out what this thing did. There's danger in just casting unknown spells from unknown tomes and scripts. But she needed more than she had...maybe the Ylissean mages could help her. She had heard of a genius witch that could help her...or at least have a lab she could use.
Or maybe Robin could. Tharja remembered she was casting magic. Maybe she would be willing to help. Tharja quickly smiled thinking of having an excuse to spend time with Robin...being near her made her tremble. She laid back on her cot and sighed contently. She knew she wasn't going to be comfortable around the Ylisseans...but Robin...Robin wasn't a Ylissean, she was something better. Something Tharja couldn't wait to get to know.