Septimus

First encountered by the party in Arc 2, Session 25, in the Xen'drik underdark. 
A Warforged ally of the party;  and either an amnesiac older companion of Fork and Bulgey, or a newer model of their friend.  Has the number seven clearly painted onto his frame.  Seems to be able to interface with the various technology that the party has encountered in the underdark, although is unsure why or how he's capable of doing so.