From the introduction:
We are all familiar with the mindless, untiring wave of zombies that taxes our resources and tires our heroes’ hearts with their fearless march into battle. But a new wrinkle got added to this familiar scene in Pathfinder Roleplaying Game: Besti-ary 2 when the juju zombie was introduced.
Juju zombies are not the mindless undead we usually associate with the word ‘zombie’. Juju zombies keep the skills and abilities they had in life and gain additional powers and protections through the conversion to undeath. The downside is that even though a juju zombie will never die due to the passage of time, its advancement in power, skills, and abilities is frozen at the time of its transformation.