Thanks guys. I honestly didn't think very hard about the fluff; I just went with something that seemed cool.
I just recently painted a Wight King and a couple of prototype skeletons. I have always wanted to do something with orange and checkers seemed like a good option to make the shields more interesting to look at. They are marked with a token black pyramid to remind the Wight Kings that they ultimately serve Nagash.
I really enjoyed painting the Wight King previously known as Krell. He is truly one of the finer miniatures in the later line of WHFB miniatures. I do however object to the idea that Krell could have possibly fitted in a regiment formation. His axe is so ridiculously huge that I had to mount him on a rather large base.