Either in USA California or in India (choose whichever you like) can a person sue oneself back for damages? Has anyone ever defamed themselves and then sued themselves for defamation?
Yes, and there can be cases this is profitable.
You negligently killed someone in a car accident.
You need to sue yourself to use your insurance.
The victim is dead so their estate goes to you.
So you sue yourself on the estates behalf, the estate wins, and you get the estate.
Directly suing yourself is impossible however.