Gate in 10,000 Bc ( Anime Gate X 10,000 BC X Primal X Dinosaurs)

Warning contains blood, swearing, and disturbing scenes that are not for children.

What if the Saderan Empire enters the Gate way too early as modern man still lives but primal beast still roams the land. How would they survive and colonies in this population lands where beast roams and waits until they will kill. Even worst the beast even ancient humans enter the gate as they search, destroy, and take what lands as it made the Saderan Empire weak and ok a verge of a Civil War. It was then a Tribe man who is part of the Wenja who have sees this enemy taking lands and enslave some of the tribes people but he wanted to unite all the tribes to defeat a foe.