These Paths were originally made by contaminating lupine Moon-Paths (see "Corruption of the Moon Path") - the Umbral pathways running between Caerns which enable Garou to travel quickly between sites, and into the Umbra. To lupines, such corrupted paths reek of death and the Wyrm, and they will almost always avoid them if possible. However, Garou may sometimes wage war to regain control of the Caern to which it is linked, and this is the great danger of Blood-Paths.
Apart from the danger of lupines, any who walk the Blood Paths must remember that there are far, far worse, and far more dangerous beings than lupines within the Umbra, that may use the Paths to gain access to the world.
The process for creating the Blood-Moon Paths is not easy (see note on Were-vampires. It is not intended to be - creation of a Blood-Path is a rare and difficult process carried out by only the most powerful, experienced and courageous Thaumaturgists, for the good of the Clan, and rarely for self-serving or frivolous reasons. This is only because it is extremely difficult, and extremely dangerous. One slip, and the thaumaturge is lupine-fodder, or forever lost in the depths of the Umbra. Even if successful, the lupines will have a particular reason to hate and seek vengeance on the Creator, and such practices serves to further ingrain the deep loathing Garou have for Kindred.
The Paths were particularly vital to the running of the Tremere Pyramid before the modern age, when travel between cities was even more perilous than today. Use of the Blood Paths, despite their dangers, was considered preferable due to their ease speed of travel. In former times the Order of Draco exclusively controlled the means of generating and maintaining the Blood Paths, and it is suspected that this strangehold on an important means of holding the Pyramid together grated with the ambitions of the Council of Seven, who with Guido removed, could steal the Order's secrets and gain control of the Paths themselves.
Today's modern transportation provides an alternative, although only marginally less dangerous, method of travel, but many Elders, and those wishing to travel swiftly and secretly, still use the Blood Paths to travel across the world. The hills above Vienna are reputed (within the Order) to be clustered with the mouths of Blood Paths, and they are one of the reasons why the Clan Tremere operates so tightly and effectively, with such a strong grip on its members, though they are scattered far and wide throughout the world.
The ritual may then take place. Those interested in the astro-spiritual aspects should note that the great secret of Blood-Path sites is that they use this pitiful victim to crudely wedge open the Gauntlet like a gaping wound - an inelegant but effective method. This is the reason why lupines find them almost unbearable - they can physically feel the pain and suffering which causes them to exist, although they will not know exactly why. Humans or anyone with a high degree of Empathy will feel the aura of pain and despair generated by these sites, and will avoid them if at all possible.
The only means of cleansing a fully-created Blood-Path (ie not one that was originally a Moon-Path, which is a natural Caern) is for a Garou shaman to destroy the were-vampire in the ground, and utterly eradicate all traces of it from the site. To cleanse the Path itself he must then perform a healing Spirit-Walk along the path, preferably aided by a high power. In practice, Garou who are going to attack vampire-created Blood-Paths will not bother with cleansing, but will merely try to destroy it, and all its occupants, utterly.