(5x21) Pantheon Synthesis: Part 1, Episode 3
The dawn of the 20th century proper sees all of mortal humanity drawn together into what they would call at the time the Great War, but which would be remembered in later history as the First World War. Resenting their subservience to the Gallic Empire that had ruled them for a century, Germania and Romania ally themselves into an "axis" to break the imperial unification of Europe under Gallia and establish themselves as powerful nation-states of their own right again, thereafter to break their alliance and seek to reconquer their own former empires.
Meanwhile, on the other end of Eurasia, the Niphon and Phillipine empires likewise ally themselves to overthrow the hegemony of Mongolia, Xiania, and India over the east. The United States of Columbia, finding themselves drawn into both of these wars through a network of alliances, unifies them both into a single global war, allying with Britania, Iberia, Gallia, Russia and Persia against the Axis powers in Europe, and with Xiania, Mongolia, and India against the Niphon-Phillipine alliance.
Near the climax of this Great War, mortal humans begin developing their first nuclear weapons, a threat that the Pantheon finds severe enough to authorize limited covert intervention to prevent. The Pantheon's attempted sabotage of most nuclear programs is successful for the time being, in both of the Axis powers of Europe, and in the United States of Columbia. But both Russia and Persia successfully deploy their own nuclear weapons, one each against Niphon and the Phillipines respectively. That act so horrifies the Pantheon that they decide to partially suspend their policy of non-interference, and while not quite revealing themselves to the mortals as yet, to begin less subtly acting to prevent mankind from annihilating themselves in the new nuclear age.