The Web was created by the fae to collect magic from the worlds they had created and, as the world in the centre of the Web, the pla
n was for Athare to have the most magic. However they didn't know until almost a century after the last world was created if it was actually working or if the whole plan had just been a waste of both time and magic, which would lead to the fae having to flee to yet another new world. This lack of knowledge didn't stop most of them from using magic as they would have done on their old home world, even though the World Creation Council attempted to teach them how to live without magic.
It later became used as the Walkers route through the worlds. Often Walkers will learn about a strand of worlds in order to make their journeys through the Web easier, otherwise they would have to use temporary tattoos in order to travel through one world to get to another. There are Walkers who simply make their choices based on which worlds they would most like to visit and have no problem with the temporary tattoos. Occasionally temporary doors are created, normally if the world the Walker has to travel through is dangerous in some way, but these never last longer than an hour. If a temporary door is created then it's always watched closely by a Walker until it fades away. The only other time a temporary door is created is if there is a door malfunction. Normally they're easy to solve, but as the doors get older there are more malfunctions.
The 'demons' have more choices as to the route they take, because of the way the magic of the worlds work. Taithmarin has no connections to any of the worlds the fae created, because it wanted nothing to do with the fae, but still allows Athare to occasionally draw off any excess magic for use by the races who have to use magic from the core of the world. It views Athare as its mother and the fae as its father. The magic it gathers can also be used by the worlds surrounding it on the Web, who it views as siblings, but this rarely happens. Gaelom, however, has more connections than the Walkers know about, that can only be used by 'demons'. If either the fae or the Walkers had tried to utilise the doors there is every chance that they would have moved.
There are, occasionally, doors that lead to hidden places, including Aerith and Kankirin, but they have their own rules. Some appear for one person who is in real need, taking them to a safe place that they may never be able to leave; others appear for a certain period of time and may disappear without being used; while the third kind, that are very rare, stay open permanently but move around continously, so getting though it is total luck and getting back is almost impossible. None of these doors malfunction, because they are created naturally, and if there are any problems then the magic that created the door fixes it before they can be noticed by anyone.
When the Web was created it took the magical strength of all the world creators, but was the idea of Riordan and Emrys. They were the first Blue family members asked to work on the creation of the new worlds, so they began by coming up with a system that would allow the magic created to move around all the worlds, and what they created was a system of tiny magic tubes. Once it was created the fae focused on the worlds, while Athare worked on making a good system better. By the time the first world was placed Athare was very happy with its work in creating gates that would allow the other worlds to choose if and when it shared magic with its fellows. The Web around Athare was the only part without these gates, because it knew that closing a gate would destroy the Web, as the Web was created using its magic.
The worlds themselves began life in miniature. It was easier than creating them as full size planets and meant they didn't waste huge amounts of magic when some of the worlds failed. All of the world creators were glad that there were very few failures, but even a few was too many, because the magic couldn't be reused. Each Blue family member worked with a different group of people for each world, once they knew the world wouldn't fail, which always included a Yellow, as they were needed to create the races. Often a Gold would be involved and occasionally a Silver, although these groups didn't always work well together.