The Portal is an extremely large, naturally formed portal.
The portal is activated every OYC, when this happens, it is possible to easily exist The Portal, by simply walking through one of its sides. However, The Portal is a finality-based structure and thus, one must go through special procedures before being able to leave.
The Portal is opened for a very short time, for about 1 OYC, which has made traveling outwards very difficult, as everything must be maticulously accurate and pre-planned, as to make it out just in time. This also means, that the person leaving can only come back the next time The Portal opens.
The objects outside of The Portal, due to it being of transfinite finality, are indescribable with finite language, and are in most cases, only described using mathematics.
In the space plane The Portal is located on, it lies facing the opposite direction in the middle of a valley of much, much larger size (The Brontavalley, a much smaller section of The Brontaplane).
It is currently thought, that The Portal is a series of singularities on The Brontaplane, which are through natural processes activated and deactivated for passage.
The walls of The Portal do not interact with anything, however, the edges of The Portal, which are quite significantly large, are completely solid and basically just a different version of a constantly deactivated portal (they are made out of different materials, but that is it when it comes to differences).