there exists a type of family that both the light and dark pureblood families have rejected; the Old Blood. the old blood families (i think there are only 1-2 in the hp universe) are extremely widespread, including absolutely anybody born or married into the family. their bodies are lined with tattoos of the family tree; given the breadth, it covers the entire body and often overlaps. these tats are usually covered by glamours.
the old blood does not support war or killing... but ! should they require it, any person in the family can draw from all of the magic in their family and use it as if it were their own.
in europe, though not advertised to the public, the opalline family is an old blood family.