In a comment on the Ghost Saber Gallery post, degbunke asked:
A little question: what does “spawned” mean in the list of cats on the site? Some of the other pets have “quest spawn” and “rare” after their names and lvls, and it’s quite obvious what that means, but “spawned”…? Is it something extra special or just a typo…?
So I thought I’d better explain.
Petopia uses a handful of tags for each creature. ‘Elite’ and ‘Rare’ are pretty self-explanatory, although it’s somewhat helpful to know that Rare is based on the in-game designation (i.e. a silver dragon portrait) and not on spawn times. (Some of the low-level rares spawn every 15 minutes.) The only other tags are ‘Quest Spawn’ — which means that the creature only spawns when someone is on the right stage of a quest — and ‘Spawned’ — and only the Ghost Saber uses the Spawned tag because so far as I know it’s the only creature that is spawned by a triggered action outside of a quest.
Incidentally, you might well ask why the change in case between ‘Quest Spawn’ and ‘Spawned’. It’s because I felt silly calling a creature a ‘Spawn’ when all creatures are spawned somewhere, somehow. But using ‘Spawned’ implied some level of just-in-time spawning to me. *shrug*
Anyway, as far as the actual details of spawning the Ghost Saber: You go to the Ruins of Mathystra in the far north of Darkshore. You find small Cat Figurines scattered among the ruins. These look like small marble cat statues and work just like a chest. When you open a Cat Figurine, there is a chance that a Ghost Saber will spawn. If one does, you tame it.
Just to complicate matters, if you kill the Ghost Saber there is a chance you will get an item called a Cat Figurine — which is not the same as the chest and does nothing — or an item called a Glowing Cat Figurine, which can be used to summon a Ghost Saber to fight for you for 10 minutes. Of course, as hunters, it’s much easier just to tame the bloody Ghost Saber when he spawns.
I also added this info in shortened form to the Ghost Saber page on Petopia. It’s not quite a mini-walkthrough, but it’s a start and I was able to cram it in before starting my real work for the day. :>