This entry contains some slight spoilers in regards to the concept that is not directly explained in books it is encountered. Line Springs represent a concept on the edge of understanding in the VayneLine universe, and as such only a few races or individuals truly know what they mean.
Line Springs (sometimes Life Spring) are an important concept that form the undertow of many plots in Vayneline. They are actual locations on a planet where Axls radiate outwards in higher densities than normal. (Axls are a dimensional, animating particle of matter that loosely can be equated with Life energy).
Line Springs are not on every planet, and even planet with Life may not have a Line Spring. They represent among other things a break in the upper lattice in the construction of reality. As such, they always have various forms of life such as plants growing nearby, even in hostile locales. (Eu-Knight, AilAid and Mirrored Sky all deal with this part of it).
Further, many Line Springs, given enough time and high enough density eventually form CAOs (Condensed Axl Objects) which are condensed Life energy and are capable of local reality manipulation.
Exposure of Line Springs – the higher density of Axls – causes the effects of increased vitality and intelligence. It leaves the telltale sign of someone’s hair and eyebrows becoming bright neon white. At very high doses Axl lines become physically etched on someone’s face.
Axls are necessary for Life, as they are the animating force of it, but at higher levels shorten the person’s life. Essentially ‘burning the candle at both ends’ thus many people ‘Axl poisoned’ die much younger, but live much high quality lives.
Because Line Springs have such high density of Axls they tend to also attract the dimensional creatures that prey on that, depending on the race they are known as ‘True Forms’ or ‘Malignant Axl Creature’.
There are only a few races that even know the basics about Line Springs other than the apparent effects of the people having increases abilities all around, or the increased chance they die to the monsters that are rarely found after the target is killed.
In general they are a huge boon to the planet, such as in Eu-Knight where a nearly lifeless planet is rendered lush due to the presence of two Line Springs (and two CAOs that had been created from them).