The primary source of conflict among the gods in Norse mythology is the Ragnarok, the prophesied end of the world which involves a cataclysmic battle resulting in the death of many gods, including Odin and Thor. This conflict is often driven by themes of greed, pride, and betrayal, exemplified by figures like Loki, who incites discord among the gods. The underlying tension between order and chaos manifests in various myths, illustrating the struggles for dominance among celestial beings and the inevitable fate that awaits them all.