Brass Man by Neal Asher

Ian Cormac, a legendary Earth Central Security agent, the James Bond of a wealthy future, is hunting an interstellar dragon, little knowing that, far away, his competition has resurrected an horrific killing machine named "Mr. Crane" to assist in a similar hunt, ecompassing whole star systems. Mr. Crane, the insane indestructible artificial man now in a new metal body, seeks to escape a bloody past he can neither forget nor truly remember. And he is on a collision course with Ian Cormac.