Thanks for your question! He wouldn't find much of anything beyond what's already in the game setting - that the moon was initially uninhabited, that the portal is a naturally-occurring phenomenon like any other, that the Quarantine was established after the Great War and all non-natural portals were shut down, in order to bring in displaced people from other universes to replenish the massive amount of lost population from the war.

Honestly, humans are not the dominant people brought in by the portal. While that may be true of the player-character population, the NPC population of the game represents a wide variety of people, predominantly non-human.