enemy twins, n.All

The Enemy twins (n.) fight ⁠​‌​​​‌​​​‌​‌‌​​​​‌​‌​​‌‌​‌​​‌​​​​​‌‌​​‌​​​‌‌​‌‌​⁠because there is no difference between them: conflict comes from the absence of difference, not from difference.