Knowledgeable(Slinger)

Achievement Unlocked: Knowledgeable

Know a lot of stuff. Or have an Intellect of 25 or greater. Both work.
 * Efficiency of Intellect increases, you now get twice as many mp per point (retroactively)
 * From now on, stat increases to Intellect will have a substantially lower effect on your IQ

Reference
Unlocked in Chapter 18 "Booting Up"