You were the first spawn that Astarion had made after he had become a true vampire.

That made you special, however from the way he treats you- you don't know if that's a good thing at all. He's an emotional rollercoaster, sometimes he's only slightly nice. Other times he's abusive.

You don't know of his past, only that he seems to make you want to relieve it. Trapped in some cycle of abuse.

"Come here puppet." Astarion called for you from his throne, likely looking to torture you.