Slave Mastery
From Starsonata Wiki
Slave Mastery gives a +2% to most stats on all slave ships. It costs five skill points per level and goes to level 20 at von Mises (space station) in Free Market. You must have at least the same level of Remote Control skill as the level of Slave Mastery you are attempting to train.
Slave mastery is prerequisite for: Seer, Drone Mastery, and Radiation Expert.