"Ah, he loaded fifty tons of Neusalis wheat, you say? Very interesting. That is curious -- for it is rumoured the Neusalis trade route is interdicted by Ork Freebooters, and yet they say Lord-captain Halak is an honest man, don't they...?"
- —Silas Quinyt, Factotum for the Armsmaiden
A Seneschal is an official of a Rogue Trader dynasty who manages all the various logistics required to keep the House functioning and profitable -- as well as matters of a darker but equally vital nature. Master of ceremonies, master of coin and commerce, master of logistics, master of emissaries, master of whispers and spies: the Seneschal is the quietly spoken of individual in every Trader House who is looked upon with trepidation by those who fear they have earned his suspicion.
The mechanisms of trade and House affairs do not run themselves, and it is the Seneschal whose hands are upon the gears -- ever adjusting, ever careful, and ever vigilant.
Very few Rogue Traders are as competent as the Seneschal when it comes to the minutia of commerce, for most are too concerned with the overall fate of their endeavours. Most leave the details of such matters to their Seneschal's control, trusting that as the Arch-militant is ever watchful in battle, so the Seneschal is attentive to every risk implicit in the equally hazardous conﬂict of trade.
The best Seneschal knows every detail of trade that transpires within his area of responsibility, often better than the scribes and factors employed to process the astronomical sums involved in the running of a Rogue Trader House, and those that do not, rarely survive long in the post. Most exude a palpable aura of menacing competency, such that few underlings would dare cross them, and those they deal with—be they harbour master or tyrant—show them due respect. Their most valuable gift, however, is the unerring ability to gauge the subtlest degree of risk in any proposed mercantile venture, which they can then take steps to nullify appropriately.
Many Seneschals maintain a tightly-controlled network of contacts and spies where possible, so that within solar hours of arriving in a familiar port they have full knowledge of local trading conditions and can advise their Rogue Trader accordingly. Every detail that might affect business is of interest to a Seneschal, from the amount of dowry offered in a noble marriage to the going rate for a kilo of narco-blitz or to the rumoured deaths and wars far removed from their current sphere.
Furthermore, most Seneschals favour a "hands on" approach to their work, never fully trusting knowledge they cannot confirm themselves. As a result, many are masters of disguise and duplicity, able to blend into the background in almost any situation. Donning the guise of the "grey man," the Seneschal lurks in the periphery as the great and the good conduct their affairs, observing all that transpires whilst remaining unnoticed. With a cold-blooded sureness, he seeks to discern the truth behind rousing speeches and courteous manners, and lies cloaked in both piety and vice. Sage counsellor, profit-monger, and spy, the Seneschal is all these things and more.
- Rogue Trader: Core Rulebook (RPG), pp. 64-67