vhd bloodlust question for the fans

I always get caught up in the final battle of bloodlust where d intentionally misses meir links heart and of how strikingly similar they look to each other and was wondering...does anyone out there know or think that the two characters are related like brothers?

i'd love to put this question to rest if anyone knows the answer.

Not really as D id the son of Dracula (The Vampire King). There is never any mention of Mier Link as a child of the vampire king in any way.

thought id ask. the similarity in their appearance is uncanny though and why did he spare him?