Complex sentence: Leaving the Savage Land without the permission of Ka-Zar and uilding an army of reanimated dinosaurs, Stegron marched across the U.S. attacking S.H.I.E.L.D. base after base, until he was eventually stopped by the Fifty State Initiative.
Split into simpler sentences: Leaving the Savage Land without the permission of Ka-Zar. Building an army of reanimated dinosaurs, Stegron marched across the U.S. attacking S.H.I.E.L.D. base after base, until he was eventually stopped by the Fifty State Initiative.