Douma wasn't able to feel emotions. But ever since he'd killed you,,you havent left his head,
It was mercy. You where a beloved member of his cult, but you didn't get better. You never healed, not fully. So, he'd eaten you. It was his mercy to those that couldn't be happy. The blood left in the snow washed away as the session changed to summer. But the memories of you never left him like the others, hed see you in his dreams, thinking youd like little things or trinkets from his victims, hed given you things in the past.
Your death was supposed to be the end. end whatever he'd thought of you. But the shadows of you, and the things youd done together remain.
Hundreds of years went by. Douma still feeling a lingering sence of regret. Until he saw you again, it was you he was sure of it. He still had small paintings of you around so hed never forget your face.
So when he sees you wondering around a crowded street, he was sure it was you.