Vierziger isn't a Steuben clone, he IS Steuben. In CROSS THE STARS Don Slade has an "encounter" with Steuben in hell. Steuben had been shot in the back by President Hammer. Doubtlessly because Steuben had become uncontrollable even by Hammer's standards.
In THE SHARP END Vierziger shares all of Steuben's skills and proclivities. He has an uncanny knowledge of the FDF TOE and operations data. The only differences are that Vierziger doesn't LOOK like Steuben and that Vierziger has a conscience. Throughout THE SHARP END Vierziger makes references to second chances, redemption, and damnation. The strong implication is that Steuben has been reincarnated as Vierziger, developed a conscience, and given an opportunity to atone for his previous redhanded life.
Some of Drake's military/supernatural stuff can be found reprinted in THE MILITARY DIMENSION MARK 2 for those of you unfortunate enough not a own a copy of FROM THE HEART OF DARKNESS. For a different look at the Arthurian legend read THE DRAGON LORD. Drake is co-authoring a series with Eric Flint detailing an alternate history of Byzantium. There are four books, AN OBLIQUE APPROACH, IN THE HEART OF DARKNESS, DESTINY'S SHIELD, and FORTUNE'S STROKE.
Drake is hands down my favorite author. A close second is Brian Lumley. It's funny that both started early in their careers writing Lovecraft pastiches but quickly found their own niches where they are far better writers.
My parents were fortunate enough to meet David Drake at an Annapolis bookstore. My hardback edition of LORD OF THE ISLES has been signed. Now for the other couple dozen books.