Family fight: The Waldgraves vs The Strykers
These two families are mortal enemies whom have agreed to a total combat (might be written into a full story).
The Waldgraves are a posh and remarkably affluent family. Don't let looks and stereotypes deceive you, this picture-perfect family is not soft. They are pragmatic, mean, well trained, and utterly ruthless. This comes out in the investment firm they run together.
The Strykers are a tightly knit modern family with a religious background. They aren't bible-thumping pacifists though, they are aggressive, fit, and very competitive. This comes out in the extreme sports and outback camping they enjoy as a family,