A race with nearly limitless power, that cannot survive in this universe.
Acirema are 10-30m long ellipsoid energy beings with "wings" ranging from 30-100m. As they age, they accumulate dust and gas eventually giving them a dusty and rocky appearance. Most Acirema live in a different universe where the laws of physics are difference, and they can only get to this universe through their "home planet" of Portal. When they reach this universe, the natural process of aging greatly accelerates. They can not survive more than a few fractions of a year here. Therefore, an Acirema rarely spends very long in this universe before returning to their own.
When the Acirema discovered Portal in their own universe, they also discovered that due to the different laws of physics energy could practically be pulled out of nowhere. They also found that their bodies could control energy. They began harvesting resources from Portal and building structures on the surface. The large amount of energy meant that they were able to rapidly mine and deplete Portal of resources.
The large amount of energy that they are able to produce on Portal gives them the edge in industry. This makes Portal dangerous to approach because they are aware of their status as outsiders and are able to produce massive amounts of weapons and spacecraft in short order. Trade with this universe, however, is very beneficial because the limitations to lifespan make interstellar travel almost impossible for the Acirema. The government on Portal is similar to that of a military or research outpost - a tightly controlled core with a loosely controlled majority. They are incredibly secretive of their society in their own universe.