Complex sentence: The Māori were warriors from many generations of trained and honed a warrior culture equals to any warrior culture including the British--survivors of the Musket Wars, twenty years of bitter inter-tribal fighting.
Split into simpler sentences: The Māori were Warriors from many generations of trained and honed soldiers of a warrior culture a formidable adversary in battle including against the British. Some were--survivors of the Musket Wars, twenty years of bitter inter-tribal fighting.