Chimpanzees kill one another and they’re just extraordinarily strong, and haven’t evolved human level intelligence because of it. Being able to rip off someone’s arms is more useful than being clever of violence were purely the answer.

The Macedonians took over the Greeks, who were more “clever” than the Macedonians. The Mongols took over China, but the Chinese are more “clever”. Scythians didn’t even have writing.

So, I think you can kill a whole lot of people without being the most cunning.