Let’s start with the Raven Mockers.  They are either know as a type of demon or type of witch that often in stories, takes on the actual body of a raven.  They stalk the sick and dying in hopes of stealing this life.  The sound of the raven is an oman of death.

The following links describes them as actually stealing the heart of the victims.  When they eat the heart, they add the days that they stole from their victim to their own.  A medicine man or woman is said to stay in the room with the dying person to protect them from the Raven Mocker.

http://www.cherokeebyblood.com/religion.htm#G 

http://cherokeeregistry.firstlightonline.org/index.php?option=com_content&task=view&id=215&Itemid=292

In the House of Night novels, the Raven Mockers are described as being half raven, half man.  It describes them that way on Wikipedia but I have a feeling someone got that from the series.

Ravens are present in many different Native American myths.  If I remember correctly, in the myths from Oregon tribes, he was part of creation.  He also is often seen as a trickster.  If you search online for raven myths, a vast majority are about him being a trickster.   

Kalona, as best as I can tell, was a character from the Raven Mocker myths.  Another way of saying Raven Mocker is Kalona Ayeliski or also Angel of Death.  The character is the House of Night novels seems to be taking these different ways of saying Raven Mocker and making them into a new myth that fits within the story.

In modern times, the grim reaper is sometimes seen as an angel of death.  Maybe it is just me but the whole idea of the Raven Mockers and angel of death kind of remind me of the show Dead Like Me.  Remember how their was those monkey things that caused harmful death?  That is what the Mockers make me think of.

Of course, in the HoN series, the Raven Mocker we get to know the best is Rephaim.   There is a couple different Rephaim references in the Bible.  One being the Valley of Rephaim.  The other is a race of giant men. 

http://bibletools.org/index.cfm/fuseaction/Def.show/RTD/ISBE/ID/7368/Rephaim.htm

This wikipedia page http://en.wikipedia.org/wiki/Rephaim  also list Rephaim as being residients of the land of the dead.   This would fall a little closer into theme with the HoN novels.

I also tried to look at Queen Tsi Sgili but the only thing that came up was references to the HoN books.  If anyone knows more about her, let me know. 

Hope this helps some people looking for info.  Sorry there wasn’t a lot that I found.