Kiara of course. Vitani said "Kiara's right. Enough." As in it was because of Kiara that Vitani realized/finally made the decision to not follow her mother.

it showed you in the movie that kiara and kovu did

Vitani remembered her REAL parents Tama and Tojo same with Kovu he remembered his REAL parents Chumvi and Kula.

^ Vitani's real mother was Zira, there was nothing in the movie proving otherwise.

I actually think Kiara's words woke Vitani up a little, so she also had a big part in stopping it. But it was much harder for Vitani to step up. She was raised to be a killing machine, and lived a hard and bitter life. Then she had to stand up against her mother- who was willing to kill her. If Vitani didn't change sides, her Pride wouldn't have switched either.

I think it was both but I don't think if Vitani agreed with Kiara the fight could have still fought

If vitani hadn't agreed with kiara there still would have been a war

If vitani hadn't agreed with kiara there still would have been a war

Kiara did. Vitani only realized from both prides are the same after Kiara exclaim to simba.

How many polls of this same question is there now? Anyways I agree that Kiara did, if she never did, then Vitani would have never changed the others opinions, it all falls back to who started the dissent, even if that dissent is a good thing there.

It helps that zira fell into the river too.