Lycanthropes are commonly referred to as "were-" animals. They are limited shapeshifters, typically having animal, humanoid, and hybrid forms. There are "True" lycanthropes and "Afflicted" lycanthropes.
True lycanthropes are born with the ability to convert between forms. They can do this at will and are not dependent on any triggering factors.
Afflicted lycanthropes are pretty much the same, except that they were not born with this ability but rather obtained it through being bitten or scratched by another lycanthrope. For them, it is a curse. These lycanthropes most often do not have full control over their form changes, and can be forced to change sometimes through triggers.
All lycanthropes are governed by the demigod Xenon.
In terms of mechanics, any evil player character (PC) may become a lycanthrope (Afflicted lycanthrope) without the need to worry about losing their alignment upon becoming a True lycanthrope. Contrary to how things were in the past, LE, NE, and CE may now all become True lycanthropes (so long as they worship Xenon).