In Ramayan, as the story goes. Vibhishan was Ravan’s brother (next in line for the throne). Ram attacked Lanka but Ravan was very powerful. Vibishan joined hands with lord Ram and told him the weaknesses of Ravan. Ram was not able to kill Ravan as he kept on standing up after getting cut in half then Vibhishan told Ram how to kill Ravan.
So they say had Vibhishan not joined hand with Rams then Ram could not have defeated Ravan. Even though being a good guy vibhishan is always remembered as ghar ka bhedi.
^^ No, Hanuman was Avatar of Shiva and helper of Ram. Hanuman is the god which has a body of ape.
Vibhishan is basically looked down upon both sides of war, and till date Ravan is considered a good guy by a lot of people.
Hanuman did burn the Lanka though when he went to Lanka as a messanger for a truce but Ravan set his tail on fire. Hanuman used the tail to burn the entire sone ki lanka.
Later when war started Hanuman also killed one of the biggest maharathi (warrior) and ravan’s brother named kumbhkaran.
There is this popular saying (idiom) in Sindhi, which means Sindh will be destroyed 40 years ago and it will be destroyed from north (Kabul/ Qandhar). Referring to northern invaders.