Those Who Came Before (often abbreviated to TWCB) is an alias given to the advanced telepathic civilization that lived in present-day Polaris space several hundred thousand years before humans reached the stars.
Evidence of TWCB in Polaris Space Edit
Kel'ar Iy, now the Polaris homeworld, has an unusual artificially constructed ring around it. This ring was constructed by Those Who Came Before to artificially "go beyond the veil", that is, transcend above a physical existance.
Tre'ar Helonis, a ringworld in the Tre'illica system, was built by Those Who Came Before. It is unknown if it was used as for farming as the Polaris use it, or if it was where the civilian population lived.
Kont, a planet with an artifical ring similar to Kel'ariy, is also presumed to have been constructed by Those Who Came Before. It was used to transport objects that were around 20 kilometers or less in diameter to a very far away wormhole, most likely not anywhere near known space.
Undisclosed theory (amateur): The only transportation was when dissidents from a distant galaxy went to ours, as they were being hunted down. After finding suitable construction sites in the above-mentioned systems (except Kontik), they were forced to "clog the hole" with a large amount of matter collected from a gas giant in the K-003 system because their "enemies" had found them. These enemies may be the Hogun encountered in ARPIA2, although both factions were presumably of the same species.