Responses
oh yeah i think the over-arching plot of the first bit (before the whole shard thing) was that the vampire wanted to drink MC's blood
i found it, but the comments dont seem bright about the end wwww
https://www.mangago.me/read-manga/baby_come_on/
I love how you answered your own question for us who got curious by your description.
there's this vampire that keeps following around mc for a reason i cant really remember and the vampire has a red(?) big shard in his chest that's maybe fragmented/a shard is seperated from his body or something. Iirc the ml (vampire) has a brother who wants the power contained within the shard, but their dad(???) gave it to ML instead. Iirc the shard contains great knowledge or something. the vampire is also high ranking but belongs to a smaller(?)/weaker vampire kingdom. I think they rule over the kingdom but theres only a few bats. One time MC called the monster(?) hunters on ml but it didnt really result to anything aside from introducing the hunter duo to the readers (i think this was displayed in a comical way). At the point i stopped reading at, i think the ML was in danger & some sort of ritual was happening due to the ML's brother wanting the shard