Why did Egypt become aggressive toward Nubia

the Egyptian king and the Nubian king both wher brothers from the same father. the Egyptain king wanted to make peace with his brother in nubia by making nubia part of Egypt but his bother turned agenst him, killing most of the pharos men. Nubia and Egypt both share the same bloodline from a man called “HAM” as its written in the bible. Ham had many sons that ruled many parts of Africa