The Bane family is a group of necromatic hobgoblins. Bane is more of an honorific than a family name, but you do have to have a genealogical tie to the family Patriarch, Heathen.
To become a Bane, you must do the following;
Be a swordsman, Raise the Dead, and dedicate your life to the destruction of an enemy of the Bane family. Most of the heads of the family also become free willed undead.
Heathen Elf-Bane, lich
Infidel Orc-Bane, ghost
Blasphemy Demon-Bane, wight
Heresy Dragon-Bane, still living
Apostasy Flayer-Bane, revenant