The Witch Class is identical as far as the rules are concerned to the class of the same name found in the Pathfinder Advanced Players Guide, p65. You can also find the information on the class on the Pathfinder SRD Website
Witches of Tulun: Arguably the most potentially dangerous of all magic-users in Tulun, Witches get access to their magical powers made with a pact with something outside the realm of the world, made possible due to the thinning of the veil between worlds after the events of The Reckoning. While a Sorcerer may possess raw magical power at their fingertips and Summoners can call forth creatures from beyond the mortal realm, Witches have a real and often powerful connection with an entity so alien and unknowable that they could literally be anything: Gods, Elementals or even Titans. Worse still, they could have a connection with those that these higher beings themselves serve. Luckily, Witches are not simply a conduit for the wishes of these otherworldly beings, but are in charge of their own actions and wills, able to make their own decisions even if those decisions might be influenced by the unfathomable whisperings of their benefactor. Often persecuted and hunted by The Church, Witches are careful about whom they trust and reveal their natures to and as such often live on the fringes of society or where their workings can go mostly unnoticed.
Witches of Enotia: Witches hold an odd place in the hearts of Enotians. While The Chruch calls them heretics and spreads word that they work with otherworldly entities (read: Titans in their eyes), and that Inquisitors have been known to hunt them down on little more than a rumour, a large portion of Witches are healers and will often help the common folk in times of need, offering spells at a fraction of a price of Clerics or Wizards or advice and knowledge for free. Therefore although Witches are technically outlawed in Enotia, the average commoner is unlikely to turn them over to the Inquisition unless intimidated to do.
Witches of Kajir: Witches in Kajir are rare, but do exist. Due to the fact the average Kajiran cannot fully contemplate why anyone who want to revere anything but the Goddess, most cannot fathom the workings of a Witch. Still, due to the fact personal merit is very important to the Kajirans, they respect the Witches choice and interfere only if they feel threatened. For their part most Witches do not settle in a land so obsessed with a single entity unless they are doing so for their own protection such as running from The Church.
Witches of Mor-Denoch: Witches exist in Mor-Denoch, but not officially. According to the Elder Council all Witches were round up and killed by Inquisitors shortly after The Reckoning, but this is far from the truth. In reality more and more people are becoming Witches in the underground Kingdom, and they are connecting with ancient beings deep beneath the earth who aid them in avoiding Mor-Denochian forces. To what end, nobody (not even the witches themselves) is exactly sure, but they are now less of a cult and more of an underground community.
Witches of Midian: On the fringes of the cities and out in the frontier, the shamen and witch doctors of the orcs, uncivilised goblins and other savage races are second only to the chief in terms of fear, power and respect. Their alliances with other worldly powers make the civilised imperial citizens nervous, maybe rightly so, but so long as the tribes continue to supply warriors and do not directly oppose the Hobgoblin elite, the witches are allowed to practice their arcane arts. Unknown to many though is the growing trend for disaffected urbanites to call on the strength of powerful beings from beyond Tulun, hoping to find some meaning or release to their otherwise intolerable lives.
Witches of Omishiru: Few Witches exist in the land of Omishiru, and those that do are usually members of the Vishkanya species who reside deep in the wilderness around the cities. Unwilling or uninterested in living among “civilised” folk, these Witches commune with what they call ‘greater spirits’ and gain their magical powers from communion with them.
Back to Classes