Undead All units with Undead have Animated Construct, Fear, and Unstable. However, they may make march moves if they are within 12" of the army's General.
Characters and Units Characters who are not Undead may join Undead units despite not being Unstable themselves. Mounted Characters ignore the Undead rule of the mount. If an Undead unit would get destroyed as a result of Unstable, any remaining character(s) will need to take a Break test as normal the same phase, using the LD modifier that they lost the combat by.