Rogue Trader: Totally NOT Space Piracy
The ship's never-seen navigator
Only Lady Augustine Castus knows why the Eldar known as Meseri decided to navigate for her. To intentionally travel through the warp, and eternal damnation of his soul requires either a lack of sanity or a highly tuned psyche, both of which may or may not be present in Meseri. Regardless, he is able to utilize the runecaster to such effectiveness that warp travel time is minimized and encounters are mercifully few and far between.