The Ancient Device, or Portals is one of the spawn points in the Aberration DLC. It is a straight forward path that leads deeper into the depths of Aberration. Although it is considered the "easiest" spawn point in Aberration, the lack of water (berries and mushrooms being the only steady supply) can present a challenge. Also the greater amount of Raptors make this area quite dangerous for survivors to actually start their journey here until the Bolas are unlocked, making the raptors easy to tame.
In addition, Tames that have survived Rockwell's boss-fight will arrive here instead of the summoning terminal unlike other maps.
A possible reason that defining The Portal as the easiest spawn point is players may inherit their level and equipment in The Island through Ascension. With weaponry used in boss fights and experience of survival, players can easily survive here.
This section may contain spoilers related to the background-story of ARK: Survival Evolved. If you want to experience the story ingame, you probably shouldn't continue reading on this section.
This Portal was made by Diana and her fellow tribe mates, which according to the explorer notes took years to make. These portals play a role in the Ascension cutscene for Aberration as the gateway to Extinction. The portal was dubbed "The Gateway Project".
Each ring on the portal has a different color, as if each ring is powered by a different obelisk, giving the portal enough power to send people down to the barren planet. According to Diana, the rings needed to scale in size the amount of distance they will travel from their ARK to a signal Santiago found on the surface of the planet.
In the story, Helena notes in Aberration explorer note #29 that the Gateway Project was strangely left intact during Rockwell's monster rampage. However, Rockwell's teaser has code that says that he allowed Helena, Mei-Yin, Santiago, and the remaining futuristic survivors to escape through the Gateway Project as their reward for putting him on a figurative Element throne.