In the Wolf's Rain anime, the goal of all the wolves is to reach a vague, nebulous goal called "Paradise". While there's a bunch of descriptions about what it looks like or where it is, what exactly is "Paradise"? Did they reach it at the end of the series? Was it just a pre-programmed, innate goal that's implanted that doesn't really exist?
Paradise seems to be largely related to many religions' interpretation of Paradise, a place in which existence is positive, harmonious and timeless.[Wikipedia]
The wolves' Paradise is a place which, to them, is a final goal they wish to reach, and appears to be very closely linked to them. As one prophecy reads, "When the world ends, Paradise will open, but only the wolves know how to find it."[Wolf's Rain Wiki] However, it is speculated that Paradise is a place which cannot be found, but must be built.
The goal of opening Paradise is achieved at the end of the series.
Cheza is the one who will lead the wolves to paradise, but in the final episode her death opens it, as the seeds that created her spill out and sprout when rain falls. In the same episode, Paradise is seen as a beautiful meadow filled with Lunar Flowers. However, after a short time, Lord Darcia's cursed wolf eye poisons Paradise, seen as a dark fluid leaking out of the eye and the white centre of the flowers darkening. The wolves never enter this paradise, instead being seen as true humans at a modern city. What can be concluded is that Paradise cannot be found, but it can be built.[Wolf's Rain Wiki]