Imagining an elf Tav who knew Astarion before he was turned because he was the older brother of their best friend during childhood. Maybe Tav is starting school, and Astarion is in his teens. And Tav falling head over heels with him at first sight, thinking he was a prince from fairy tales. Crushing in the way that many children have a crush on their friend’s older sibling.
Tav blushing and nervous and giggling whenever Astarion is in the room. Tav hoping to see Astarion whenever they go their friend’s house to play. Tav being teased by their best friend for their crush on their older brother, and both their families and all others knowing about Tav’s crush on Astarion. Tav doodling Astarion and his name in school journals, writing their name as “Tav Ancunìn” with little hearts all around. Tav fantasizing about them and Astarion getting married in the cheesiest, rosiest way possible. Tav’s day being made whenever Astarion acknowledges or speaks to them.
Also Astarion being an absolute menace in the way that older brothers are. Making fun of Tav and his sibling. Talking down to them. Disrupting their games and threaten to decapitate their dolls or stuffed toys -- And I can say that because my brother used to shoot me and my best friend with a rubber band gun that he made himself with legos, and my uncle really would decapitate and execute my mom and my aunt’s dolls.
Tav and Astarion’s sibling squabbling back. Insulting him, taking revenge on their toys by assaulting him, ruin his clothes and hair, disrupt and steal from his room. Yet despite the age difference conflict between them, Tav still looking forward to seeing Astarion whenever they can.
Tav being distraught when Astarion leaves his family home to study law, and them still being too young to follow him in his grown up path. Tav being there for their childhood best friend when Astarion is killed, while also grieving themselves. Tav going through their life, meeting new people, falling in love, pursuing relationships, and ending them at their time. The tale of their crush on their best friend’s brother Astarion being a funny and bittersweet anecdote they tell to anyone interested, the hint of nostalgia always in their tone.
Then Tav gets snatched by the nautiloid. And they see Astarion on the cliff, for some reason alive, for some reason with eyes red. They are shocked and confused. Is this the real Astarion or someone imitating him? Wasn’t he supposed to be dead? What happened to him in these 200 years? Maybe Tav understands Astarion not remembering them, likely they were just his younger sibling’s friend and nothing more. But he doesn’t even remember his sibling or the rest of his family? What happened to him?
Tav horrified by the reveal that he is a vampire, that he has been one for 200 years. Some questions are answered, and others pop up with the revelation. They offer him blood because even if he became an undead creature he is still the person they loved as a child, they can't just leave him on his own.
As Astarion starts making advances, Tav being conflicted over their previous crush being suddenly back in their life, and needing to negotiate over their childhood feelings, and the knowledge that they don’t know this Astarion. An ample dose of second-hand embarrassment over their behavior towards him as a child. Gods, they used to write his name in their journal like a creep! The contrast between their innocent childhood crush and Astarion's heavy flirting gives them whiplash. There are moments when Astarion pretends to know them, to weaponize their previous feelings by making assumptions. Those moments spark Tav's anger, making them snap at him. It makes them want to categorize the younger Astarion that they loved, an this current selfish, mocking version of him into two different people.
Yet, Tav finds themselves falling for him again. It feels surreal, their child self would faint at this development. They're overwhelmed by the attention, and also wonder why despite the flirting and sex there still seems to be distance between them and Astarion. But they want to be next to him again, drink in the attention that he gives them. They show him his scars, banter back and forth, they tell him anecdotes from their childhood involving him and his sibling, including the ones in which Astarion would torment them. Astarion often doesn't remember, but that's alright with Tav. Just the fact that they are able to spend time with him again is enough.
When Astarion confesses his plan, it hurts. Badly. That he planned to use Tav's feelings, both their childhood's and their current ones, in this way. Him admitting that he got close to them in part because Tav knowing him before made them an easier target for his plan, as well as his curiosity over who he was before he turned. And it's unbelievable that he would have feelings of his own for them. Whether they immediately decide to believe him, or are always wondering whether Astarion means it when he says he wants to pursue something real, The fact that Tav cares deeply about him once more is unmistakable.
Tav wishes they could have been able to do something, anything, so that Astarion wouldn’t have been under Cazador’s grasp. Each time they learn something new about his tortures, the guilt becomes immense to the point of feeling intolerable. Why didn't they search for him after his "death"? Why did they never encounter him whenever they were in Baldur's Gate. In the end, bitterly, both Tav and Astarion agree that Tav couldn't do anything. They thought he was dead after all. And what would a child have doner against a powerful vampire lord?
Astarion wishing that he could remember his childhood, remember Tav as an innocent bright-eyed child and how they acted in front of him. Him incredulous that Tav would have feelings for him even when he was most unsavory ("Decapitating your toys? Are you mad, darling?"). Him feeling jealous over that version of him lost to time that captured Tav's heart so thoroughly. Astarion collecting every single moment in the now where he gets to feel at ease, cared for, safe with Tav. Each one of them being a most precious gift. Wanting desperately to tell them he loves them, but not wanting Tav to think about him as that charming young boy.
Tav thinks that what they built with Astarion is very different from the fairy tale romance that they imagined with him as a child. But maybe it's better, because now they get to know every facet of him, the good, the very bad, the very very ugly, and they're able to choose him all the same. And Astarion is able to do the same back. He's not their friend's older brother that they loved and admired from afar, but the man standing right next to them as an equal. A man who might struggle to be honest with his feelings, but that it's unmistakable that he loves them.
Anyways I'm rambling, but I think it would be neat :)