I am not necessarily a guru on BD, but I assumed that it was just a quest that ended with the delivery of the sword. The sword appears in the "general stuff" tab along with food, etc., so it does not seem to be usable....
I did a few Temple quests after getting the #1 Ranking--quests are nice XP usually, but other than that once you can talk to the Black Bishop, they are optional....not required to advance the game story... <img src="/ubbthreads/images/graemlins/delight.gif" alt="" />