There are four yugas (Era) widely accepted in Hinduism. They are : 1. Satya yug 2. Treta yug 3. Dwapara yug and 4. Kali yug. In Satya yug, the fight was between two worlds (Devalok and Asura lok). Asura lok being the evil, was an entirely different WORLD. In Treta yug, the fight was between Lord Rama and Ravana took place. Both rulers were from two different COUNTRIES. In Dwapara yug, the fight was between Pandavas and Kauravas happened. Both good and evil from the SAME FAMILY. Kindly note how the evil is getting closer. Now, do you know where the evil is in Kali yug??? It is inside us. BOTH THE GOOD AND EVIL LIVE INSIDE US LIKE EQUALLY POWERFUL WOLVES. And in the battle between these two powerful wolves who do you think wins? The one you feed the most! This is probably the greatest and most subtle teaching of Hinduism, that the real battle with the evil will take place inside us in the future.