This is quite a common setup in Japanese manga. A youthful looking member of a long-living species picked up a human child, raising them, and then the child grows up to be a young adult with lots of FEELINGS for their parental figure. What sets this story apart is simply that a) it is BL, and b) the long-living immortal here is a femboy vampire. With that understanding, I come here with full awareness of what I'm getting to. A bit of grooming made tasteful and affectionate, a bit of size difference, a bit of age gap brushed aside to not make it look problematic, a bit ofcute chibis in the flashbacks, and so on, and so forth.

And femboys. Tons of femboys.

If you're ready for all of this...I think so far, so good?

Raul, the human, is totes adorbs as a stoic child. Raul as a young man is hunky and dependable, and yet still very charming in his earnest desire to protect Rose. Rose is beautiful and graceful, and when he has to be deadly, the story also manages to portray that as well.

Their relationship is clearly, CLEARLY, loaded, and in the currently available story it's clear that the story is heading towards romance (or at least moving past 'just adopted family'), and yet there's nothing overt happening just yet. Most of their interactions is just warm and tender and caring.