The four war gods seemed to be of the elements: Earth, Air, Water, and Fire.
Where as normally as in InuYasha the Movie: The Castle Beyond the Looking Glass the elements were Earth, Water, Wood, Metal, and Fire. Why did they change?
It seems to me that the four war gods are based off of the Four Gods (like in Fushigi Yugi and of course, the corresponding demons int the anime) - Suzaku, Seiryuu, Byakko, and Genbu which each have corresponding elements:
Suzaku - Fire - Kyora
Seiryuu - Water - Ryura
Byakko - Air - Jura
Genbu - Fire - Gora
Metal and wood are sometimes included when discussing them elements, sometimes not. I don't know if it's a matter of Daoism or Shintoism or another deciding factor besides religion (feeling a little lazy in the research department today, sorry!).
Life is like a toaster - you gotta be pushed down before you can pop up.