In regards to Bosch, Degenerates are beings that were once living, sapient creatures, but who -- for one reason or another -- succumbed to the corrupting magicks of Bosch, and are more or less bound to it for the remainder of their existence.

Bosch, a realm of wild magic and magical "illusion", can be quite harmful to those who enter it. Aside from the possibility of simply being slain by its inhabitants, there are numerous ways in which one's form might be altered in such a way that -- while one might be sustained by the magic of Bosch, where physics seem to only sometimes apply -- one would not be able to survive for long outside of this Forbidden Zone. This appears to not only be a physical but a mental transformation, as persons with strong wills and strong faith have been known to be able to resist ... at least, for a time.

The process is greatly accelerated if one makes the mistake of consuming anything while in Bosch. After all, the sustenance one receives from food or drink of illusory origin is not real and physical. A person sustained on food and drink in Bosch for a prolonged time (and nobody really knows how long a "prolonged time" actually is) would eventually have much of his or her physical form replaced by magical substance ... a magical substance that would disintegrate once the person was removed from Bosch.

Therefore, Degenerates are persons who have reached a state where they may be weakened by leaving Bosch ... or might simply disintegrate outright. There may be hope for a Degenerate in the earliest stages ... but even something so simple as eating a single piece of illusory fruit, or taking a sip of illusory water can open the door for Bosch's magicks to take over the victim's body in insidious ways. Furthermore, being a Degenerate does horrible things to one's sanity.