Let us collect what we already know about the history of New Romulus and the last days of the Dewans.
- The Dewans started out as a species of bold explorer, but ended up as a servant race to the Iconians.
- The revolt that destroyed the Iconian Empire also made the Dewans go extinct and made their planet uninhabitable for a long time.
- The Proto-Romulans, on their way to a planet suited for their needs, lived on New Romulus for some time.
According to the "history of the Dewans" tablets from the T3 instance, they stumbled across the Iconian gate later. They tried to reactivate it powering it with geothermal energy. Something goes wrong, they get a massive problem with volcanic activity and go extinct.
Alien overlors that are referred to as gods and use gates for travel, where do we know that from?
- the Dewans were a subject race of the Iconians
- during the rebellion against the Iconians, Dewa III was nuked from orbit. Most of the Dewans died off, while the Iconians escaped through the gateways
- the Dewans eventually created a civilization not unlike 21st century Earth
- they were on the brink of building their first warp ship when they discovered an Iconian gateway in an underground cavern
- they abandoned space exploration in favor of fixing up the gateway
- they connected the gateway to geothermal taps to power it
- when they activated it, it triggered tons of seismic activity -- volcanic eruptions, huge earthquakes, tsunamis, etc
- the surviving Dewans retreated into caves, and eventually died off when their resources ran out
"It's not safe out here. It's wondrous, with treasures to satiate desires both subtle and gross. But it's not for the timid."