Forbidden Lore
Rather than risk losing his magic, an eldritch cultist using forbidden lore instead has a 15% chance of becoming confused for 1d6 rounds. Every time the eldritch cultist uses forbidden lore, the chance of becoming confused increases by a cumulative 5%, but resets to 15% after the eldritch cultist fails this check. Confusion can be given to another creature via channel punishment as normal, and creatures normally immune to confusion are not immune to this backlash effect.
This alters forbidden lore.
Eldritch Knowledge
At first level, the eldritch cultist gains Divination as a bonus sphere. This replaces the invocations class feature gained at 1st level - the eldritch cultist gains access to invocations at 3rd level, but counts his eldritch cultist level as two lower for the purposes of determining which invocations are available to him. This archetype remains compatible with archetypes modifying or replacing invocations, but gains those invocations or their replacements two levels later.
U: Part of Ultimate Spheres of Power and does not need to be bought separately from that book