The information here comes from the Sabriel Trilogy by Garth Nix. The books can be found in the young adult fantasy section of you local library or book store. If you have never heard of the Sabriel Trilogy, I would suggest that you go read that node before proceeding with this one.

In these books, the Abhorsen is a necromancer who’s job is to bind the Dead that have made their way back to life with the help of other necromancers. Abhorsen is a hereditary title. The parent teaches the child the techniques for dealing with the Dead.

Five great Charters (bloodlines) knit the land.
Together linked hand and hand.
One in the people who wear the crown.
Two in the folk who keep the Dead down.
Three and five became stone and mortar.
Four sees all in frozen water.

- From Sabriel by Garth Nix

It is said that the Old Kingdom cannot prosper unless the bloodlines are strong. The Abhorsen line is in the most danger because they do the most dangerous work and because the line has nearly died out. The Abhorsen must walk the river of death to the very foot of the ninth gate with only his (or her) sword and the seven traditional bells of a necromancer. From smallest to largest the bells are: Ranna (the sleep bringer), Mosrael (the waker), Kibeth (the walker), Belgaer (the thinker), Dyrim (the speaker), Saraneth (the binder), and Astarael (the sorrowful). The Abhorsen’s sword has a magic on it that allows it to do permanent harm to Dead flesh. It’s inscription usually reads, ”I was made for Abhorsen to slay those already dead. The Clayr saw me. The Wallmaker made me. Abhorsen wields me so that no Dead my walk in life, for this is not their path
Abhorsens have pale skin because forays into death leech the color when they can’t touch the life within and they usually have black hair. Their ancesteral home is on an island just above a waterfall on the Ratterlin River. Their symbol is the silver key.