We would have read in the ancient puranas, about the penance of Demons on Lord Brahma, and getting great boons after finishing their penance. But most of the demons have utilized their powers obtained through their boons only for destructive purposes. After getting great powers, through their powerful boons, they began to capture the divine worlds and used to control the demigods, and lived a comfortable life by drinking wine and enjoying great pleasures in their life. They also disturbed the sages and spoiled their Yagnas. And since they had great powers through their boons, no one could control them.
Finally in order to destroy them, the gods or goddesses have to take an avatar to kill them. Why this is happens? Why can’t the gods avoid giving the boons to the demons?
The reason is they could not stop giving boons, since the demons have almost sacrificed their life and performed the penance. The reason for giving the boons to the demons and killing them is mainly due to the changing situations, which prevails even in the divine world.
There would be some changes even in the life of the demigods, since they also cannot remain happier for ever. The divine gatekeepers of Vishnu had incarnated as demons in their three births, and destroyed by Lord Vishnu, and finally they went back to the Vaikunta. All this happens, due to illusion, and even the gods cannot escape from that.
Vishnu was cursed by Sage Bhrigu to lose his wife in an avatar. Similarly Lord Vishnu had incarnated as Rama, and Sita was kidnapped by Ravana, and Ravana was destroyed by Rama. All these things have written already in their fate, and Mata Sita played a major role in destroying Ravana. Life would not be always sweet even for the divine gods, and they also adjusting their life as per the changing circumstances.
Let us worship Lord Rama and be blessed.