Why did Genghis Khan feel the need to fragment the Mongol tribes into new social and military groupings?

Many Mongol tribes lived in the Steppe region. They had their own different identities. Genghis Khan wanted to unify them by raising their different identities and create a large community with different social groups and tribes. That’s why he felt the need to fragment the Mongol tribes into new social and military groupings. He created those groups as his military and established a dreadful empire.