Windwalls

Windwalls serve as the invisible walls in Journey. When a player gets close, the wind will start to blow. If the player tries to walk or fly through them, the wind will eventually blow them back.

The fifth Confluence suggests that they didn't exist until after the Ancient Rythulians died from the war, before the Wayfarers existed.

Bypassing the windwalls is often needed to get Out of Bounds.

Development
In Level 09 - a left-in beta level - the windwalls show as a number of unanimated, round clouds of dust.

Speculation
The windwalls could be meant as punishment, isolating Rythulia until proper atonement is made. They could also be meant as protective barriers, helping the Wayfarers to stay on their path, possibly preventing outside interference.