My updates:
We have had a "peace" pact. He got a promotion recently and is in a position similar to mine. He definitely had insecurities because of me. I got more independent role; I pick my own projects and mostly the difficult ones. And I will get a promotion from mid year. GC is already under process. He does not have strong subject matter knowledge. I exposed him. Now he asks me questions whenever he has. I answer those with a smile in my face. Feels good to see a part of his self dying inside. Like many suggested, I ignored him. He came back to me making conversations whenever he could.

BTW, @gaulejetho, I wanted to respond to your comment a long ago but let it go. Buddy, not all people work for Indians. Nor do they want to, for that matter. Probably you do. Even if you do, you don't have to apotheosize them. I know how Indians treat their subordinates. People like you that prostrate to Indians are the reason these people think that they are master of us Nepalese . Just treat them as your employer, not master. Huge difference. I have, btw, very firm legs, well planted to ground. Great weekend!!

I had a Bengali friend back in the school. He said, it took him 2 hours of cycle ride after getting off of a bus to get his home. Still, he asked me one day, "Hey, do you people have a newspaper in Nepal? airport?" Like, we have not seen Bengal. Superiority complex is badly ingrained in their soul. They think they come from some first world country and Nepal is a "poor" country for them. Bollywood injected fake grandiosity. They come hurling down to the ground, just show them their real face.