I am not sure, if this belongs here or if that is supposed to be this way, so I hope it dosen't bother you.
As the Athame is made from silver, vampires can not use it, without being hurt. However, the athame is the only way to obtain bloodbottles currently, without wich vampires die. So it would be usefull to either add another way of obtainig blood or make the athame not hurt vampires.
Again, if this is wrong here I am realy sorry, but I didn't know any other place to mention.

It's fixed in dev

The primary way of getting blood is by drinking directly from the mob, but yes this is already fixed