Author here, I just wanted to say that I did this for fun, I had a little idea because of a drawing and wanted to do some angsty Robin X Tharja, of course that in the next chapters (I have 3 planned so far) the sweet part in bittersweet will outshine the bitterness, also my grammar sucks so yeah, you have been warned.
Grima, The Fell Dragon, Robin. They were all one and the same, fate did not care whether or not one believed this to be true, it was an irrefutable cruel truth.
After the bonds they created, the shepherds did not care, after all they went through Chrom did not care, after falling in love Tharja did not care, Robin was still Robin and they would fight fate itself to prove it, in this case they were doing something just as difficult, or even more so.
Grima. After Lucina's stories of their future they could hardly imagine how hard it must have been in that destroyed timeline, but now that they were facing the demon behind such a catastrophe they did not have any sort of difficulty trying to imagine how that future came to be. To prevent such a thing from happening, every single shepherd was fighting with all their might, Grima's minions were far stronger than any Risen or soldier they had fought, but they made it this far with their strength as a group and Robins tactics which always seemed to be enough to turn the tables, surely this time would be no different!
Everyone was fighting with at least another Shepherd, to be sure no one would be overrun and so they could slowly make their way to Grima, whenever an archer targeted a Pegasus, someone would deflect the arrows and magic would pierce the archer, while the knights who soared the skies made sure to in return take care of any separated minions who tried to flank the Shepherds, Chrom and Robin standing in the front like an unstoppable force, but even they needed help as well which came from their wives, Tharja always behind Robin and being in complete synchronization with him, adding to his defense and attack whenever it was needed and Sumia soaring directly above Chrom, distracting his enemies with Javelins as Chrom cut them down mercilessly.
Even so they were far from unstoppable, not one Shepherd was without wounds, after all they were not facing any ordinary foe, not even humans who had to worry about stamina, breathing, and emotions, but they had no time to worry about any non-fatal wound, not when the fate of the world rested upon their shoulders. Heavy breathing, bleeding and exhaustion, a trait almost everyone shared at the moment, but now that Chrom, Sumia, Robin, and Tharja stood in front of Grima they had only one thing in mind, to seize victory.
They did not underestimate Grima, they had been extremely careful in their every move, but there was no way they could ever know just exactly how strong Grima was, Robin and Grima were one and the same, all the tactical prowess Robin had, Grima had taken for himself as well, giving them a false illusion of hope would take away their attention from the battlefield for a few seconds, just enough for Robin and Chrom to step on a magic-mine, they had no time to react to it, simply enough for them to realize they had failed.
Grima anticipated everything, the power of a dragon and one of the most powerful minds in the kingdom, if not the world? A monster, too powerful for them to ever defeat…but not even Grima anticipated one thing. Tharja.
Since the moment Tharja met Robin, she could never take her eyes away from him, she knew everything about Robin, from knowing how many times he turned in his sleep to the fragrances he enjoyed the most, it was the man he loved with all her heart, the man she hoped to meet for so long and now that he was in her sights she would never turn away, always staring at his comforting back, always loving him, always protecting him. Always.
Tharja knew of the trap once Robin and Chrom stepped on it, she felt the magic trigger but could not tell them about it in time, all she could do was selflessly throw herself in harms way to push Robin away from it, no one will hurt Robin, not while she is still breathing. Thankfully Chrom's armor and sword managed to deflect the spikes that came from the floor, his quick reflexes letting him be pierced only once in his shoulder, but far from enough for him to stop fighting. Tharja had no armor, no quick reflexes, no weapon to parry the spikes, no plan, simply a wish to protect her beloved, as long as he was fine it would be the same for her.
The spikes had cut Tharja in various places, legs, arms and a spike barely missed her stomach, but it was big enough for it to pierce the side of it, making her bend over in pain while her hand pressed her side, blood quickly spilling from it. She was still alive, breathing harshly and honestly it was a miracle as to how she was still standing.
Grima and Robin both had the same expression, to Grima, it was due to his plans being foiled by a fool who cared far too much for Robin. To Robin, it was anger, plain wrath at himself for falling in such an obvious trap and having to be saved by Tharja, leaving her in such a sorry state and towards Grima for hurting Tharja, the girl who cared for him whenever he was sick, whenever he was in trouble even if it meant no sleep for her, even if it meant she would harm herself, like now.
It was as if the world stopped for a moment, all Robin could hear was Tharja's rough and weak breathing, seeing how her legs struggled to support her weight and how she could barely hold her own tome, how blood and cuts seemed to cover the dark mage, the amount of sheer pain and exhaustion in her face, it was all Robin could concentrate on, seeing the life of his fated one slowly drain from her body.
Grima was at fault, Grima had to pay, Grima had to die, not by Chrom's hand but by his, he had to make sure he would never be reborn, that he would never hurt her again, that no one would! Revenge, a dark magicians most powerful weapon, Robin may not have been a dark mage, but he had the power of one, a pungent and dark energy enveloping him, as if the hands of the undead were slowly gripping his ankles and they were making their way up, it was a heavy feeling and it wanted to come out, it screamed in his ear to be let out towards Grima, the one at fault. Robins eyes screamed for revenge, his hands instinctively being held up together to gather energy, but it wasn't lightning as usual, it was far darker, far stronger, far bigger than any spell he had ever used before. Dark magic, a dark gigantic orb of pure hatred and thirst for vengeance, enough to make Grima take a step back on pure instinct.
Robin unleashed it all towards Grima, not caring for any sort of tactic, any sort of all-out attack with Chrom , as long as it hurt him, as long as it crushed him, as long as it made Grima bleed and die a hundred times over he was satisfied, sadly he had even forgotten about Tharja, he had forgotten about the sacrifice Tharja had made, he only wanted to inflict pain, he wanted to destroy Grima whatever the cost, even if that cost was himself.
The attack was powerful, to the point Grima had to use all of his magic to defend himself and every minion disappeared in an instant to make it possible, it was not enough to kill Grima, but it weakened him substantially, allowing Chrom and Robin to get close enough to deal the final blow, of course Robin was approaching Grima with every intent to kill him, even forgetting he would die if he did so, once Chrom saw Robin already charging up his next attack he immediately held him in place by grabbing him, to his surprise Robin struggled for a few seconds before Chrom managed to get him back to his senses, Chrom knew Robin was angry but he felt there was much more to it than that.
"Peace friend, I want to end this war as much as you do but remember…if Grima leaves this plain of existence so will you, let Falchion be the one to pierce Grima." Chrom offered Robin, after all Robin was too good of a man to leave this world, when the time comes Grima shall be defeated again, but Robin wont ever come back.
Robin bit his lip in frustration, looking back to Chrom he could see Tharja in the corner of his eye, limping to where they were with Sumia helping her, it was shameful that he didn't even help Tharja when she needed it, even now he felt it was too late to do so, as if he didn't deserve to go help her after what happened. "Chrom…let me do this" The tacticians expression changed, he was decided, Chrom could tell what Robin thought from the look of his eyes, after all they had spent years together and both learned a lot from the other, Chrom came to learn that look meant Robin had taken a decision and would not back down, and that gave Chrom even more reason to be as surprised as he was.
"No, Robin we can-" He wanted to plead the man, convince him even if he know it was useless, but Robin had already anticipated it and interrupted him.
"CHROM…Grima killed thousands upon thousands in the future, even now our army barely made it alive, look at our soldiers and tell me with complete confidence we can be sure Grima will be defeated once more, even if he is who is to say many wont lose their loved ones? Who is to say half the world wont be in ruins when they fend off Grima? I would have probably died if it hadn't been for Tharja and look at the state she is in!" Robin's tone had gotten more defensive and angry at the mention of his wife almost losing her life, desperation clear in his voice the more he talked and shared his reasoning with the Exalt.
"My job is to protect every man in this army, to come up with the best tactic for that…and my job as a husband is to protect my wife Chrom, which I am sure you understand perfectly as a father and a husband yourself. Even after Tharja pushed me from harm's way, all I could think of was Grima's destruction…how he hurt so many people, how he almost killed Tharja…it made me realize just how true it was, just how much Grima is me and I am Grima, therefore I must kill him, to prevent him from harming any other being again, and to prevent myself from going down that path…" Robin smiled peacefully, his resolve crystal clear as his words turned into a gentle tone, his hand gathering the same dark energy he had used a few minutes back.
"I can give my life to protect those I care for…" Robin wished he could have spent more time with his friends, at least give his goodbyes properly, he had made so many promises to them and now he wont be able to fulfill any of them, Tharja will probably get mad at him for it.
"What do you think youre doing?!" Tharja screamed, not believing the scene in front of him. "You promised Chrom would deal the final blow! I told you Robin, you will have to face me before going back on your word!" Tharja limped towards Robin as fast as her wounds allowed her to, a mixed expression between pain and anger in her face. She stopped in her tracks once she stood right in front of Robins back while holding her side, Chrom and Sumia quickly walking to her side to try and calm her down, otherwise her wounds might get worse.
That scene was painfully familiar to Tharja, Robin charging up a spell while she stood behind him, all her attention directed towards his back, admiring the way he stood, the power, the confidence, the way he protected her in battle. She was always smiling, loving every second of standing behind him, not being able to see his expression only making his fantasies run wilder, making her feel pure bliss…but this time was different, his confidence was gone, her smile was gone, the way he was protecting her made her happiness turn into sorrow, the way she couldn't see his expression was killing her, the way his back looked so distant made her fume in anger. "Why are you not saying anything?! ROBIN!" She screamed at the top of his lungs, scared that he would vanish without a word, angry that he would vanish without a word!
All Robin did was turn his head towards Tharja and give her a smile, the more pure smile she had ever seen on him, even more so than when he was sleeping, even more so than when he proposed, which also was the saddest smile Tharja had ever seen on the tactician, she no longer wanted him to talk anymore, she was afraid of the words that would come out but she wanted to hear them as well, she wanted to hear what Robin had to say for himself for going against her this way, the pain and confusion she felt in her head was way worse than any of the wounds Grima had given her. "Tharja—" Tharja closed her eyes and covered her ears, trembling and in fear. "NO! I DON'T WANT TO HEAR ANY OF IT!"
Robin's eyebrows shot up, and then once more his face fell to a gentle expression, he was afraid as well, after all what would happen after he vanished? What would happen to Tharja? Chrom? He didn't want to leave, he wanted to live, but he was a tactician and a husband…he was Grima, there was no other choice. "Chrom, take care of Tharja for me okay? She might hex you once or twice, but its nothing the great Exalt can't handle right?" Robin jested, probably for the last time he ever would, finding it even funnier because of it. Chrom wanted to say something, but sometimes it was best if you said nothing and all, with that in mind he chuckled as well, nodding at Robin, letting his best friend understand it was a promise. Chrom also knew the meaning behind those words and held Tharja back, knowing fully well she might throw herself to make sure Robin didn't land the final blow, Tharja was surprised at the sudden grip and knew immediately what it was for, making her struggle immediately with all the strength she had left.
"Forget saving the world—I just want you! Gods have mercy on anyone who interferes! CHROM, LET ME GO OR I SWEAR I WILL-" Tharja tried to shake off Chrom's grip, but she barely had any strength at all, it was frustrating, it was too frustrating! Robin didn't want to leave in such a sour note, how could he call himself a good husband if he couldn't even make his wife smile before leaving?
"It was fun right? I really was looking forward to tonight's date like I promised…I should really stop making promises…but I can assure you, I was happy I came to have you as my wife, I know you would do anything for my sake…so please, don't do anything reckless and stay with the shepherds okay? I won't be able to be part of your happiness, but I wish for it all the same Tharja, I love you…thank you for everything, please tell the others my last thoughts were of them as well…may we meet again, in a better life…" Robin gave his friends one last smile before turning to Grima, delivering the final blow and ending this cursed and meaningless war.
Grima had no means to defend himself and succumbed to Robin's final blow, now that Grima had no life force left he began vanishing into a dark violet smoke which got blown away by the kind, until Grima was no more. Grima and Robin were one and the same, both Grima and Robin vanished, both Grima and Robin were no more.
The world had been saved, the war had been won, but there were no smiles, there were no celebratory speeches, no shouts, no celebrations, only a bittersweet pain on everyone's hearts, only tears strolling down the cheeks of everyone, only people mourning the pass of a dear friend and the best man and tactician they came to know. The only sound everyone could hear was Tharja's scream of anguish, even Chrom's pain seemed to be nothing compared to Tharja's, she could only fall to her knees as she cried, the sight of Robin's back disappeared, she had no place in this world anymore, she had no reason to be anymore, how could she pursue happiness in such a world? Tharja's body could not take it anymore, fever had struck in and the pain was too much, she was forced to pass out due to the heavy toll the wounds had taken on her body, Lissa immediately ran to her side and try to heal her as much as she could before tending to the others. This was not the scene of a war that had been won, but they would not let Robin's sacrifice be for nothing, nor simply stay with their arms crossed, the possibility of Robin still being alive like Naga said, they would look for him the rest of their days if needed, Tharja definitely would and Robin knew of this which is just another reason as to why Robin asked Chrom to take care of her, that is why Chrom will help her, after all every single soldier had the same thought.
Robin was out there, somewhere, they just had to look for him.
Chrom noticed something in the corner of his eye, he walked to where Robin was standing and found a dark cloth and a tome on top of it, upon closer inspection he recognized them as Robins cloak and his favorite tome involving tactics. Was this fate reassuring them they would encounter Robin once more? That part of him was still alive? Chrom didn't know, but Grima and fate itself had stood against them more than once, whether it was still not on their side it didn't matter. Chrom smiled to himself by remembering that they found Robin on the floor the first time they met as well, he had the idea of where to look for the man but that would come later. Chrom took the cloak and tome, knowing fully well Tharja deserved to have those more than anyone in the army, he would take care of them until she woke up of course.
As Chrom walked over to Lissa to ask what she could help the injured shepherds with, Chrom noticed Tharja was shaking due to the fever, tears were still coming out of her eyes and she kept mumbling Robins name, it was heartbreaking. The scene had destroyed Chrom's positivity immediately, his smile turning into a sour frown. He then gently placed Robin's cloak over Tharja and his eyes grew wide, Tharja had instinctively gripped it and hugged it, due to being so used to Robin's scent and warmth and having done so multiple times, she just had to feel it for half a second before reacting to it, the pain in her expression quickly fading as she seemed to enter a deep and peaceful slumber, perhaps dreaming Robin was still holding her, allowing Tharja to experience one last moment of peace until she woke up, it was what she deserved, it was definitely what Robin would have wished for.