Deep Space Nine: Section 31 - Abyss by David Weddle and Jeffrey Lang

Blurb:
SECTION 31™
They are the self-appointed protectors of the Federation. Amoral, shrouded in secrecy, answerable to no one, Section 31 is the mysterious covert operations division of Starfleet, a rogue shadow group commited to safeguarding the Federation at any cost.
Mere days after the startling events of AVATAR, Dr. Julian Bashir faces his darkest nightmare when Section 31 compels him to undertake amission to stop one of their own. But this renegade is no ordinary agent. Like Bashir, Dr. Ethan Locken is genetically enhanced, a human superior in body and mind. But Locken dreams of remaking the galaxy in his own image -- and creating a new human empire based on the example of the infamous Khan Noonien Singh.
And as he begins to understand the terrifying truth about his opposite number, Bashir will learn more about himself than he ever wanted.
NO LAW.
NO CONSCIENCE.
NO STOPPING THEM.
______________________________
I actually read (the German translation) of this one before I read the Avatar duology, simply because Heyne (the German ST publisher back then) published the S31 miniseries, but didn't publish the rest of the DS9 post finale novels. So I was a tad confused at first because of the new personnel and constellations among the characters. But even without the knowledge from the previous two books I really enjoyed the book and thought that it was a very well written piece. Once I had read the Avatar books, I reread the book and liked it even more.
German cover (Cross Cult reprint):

SECTION 31™
They are the self-appointed protectors of the Federation. Amoral, shrouded in secrecy, answerable to no one, Section 31 is the mysterious covert operations division of Starfleet, a rogue shadow group commited to safeguarding the Federation at any cost.
Mere days after the startling events of AVATAR, Dr. Julian Bashir faces his darkest nightmare when Section 31 compels him to undertake amission to stop one of their own. But this renegade is no ordinary agent. Like Bashir, Dr. Ethan Locken is genetically enhanced, a human superior in body and mind. But Locken dreams of remaking the galaxy in his own image -- and creating a new human empire based on the example of the infamous Khan Noonien Singh.
And as he begins to understand the terrifying truth about his opposite number, Bashir will learn more about himself than he ever wanted.
NO LAW.
NO CONSCIENCE.
NO STOPPING THEM.
______________________________
I actually read (the German translation) of this one before I read the Avatar duology, simply because Heyne (the German ST publisher back then) published the S31 miniseries, but didn't publish the rest of the DS9 post finale novels. So I was a tad confused at first because of the new personnel and constellations among the characters. But even without the knowledge from the previous two books I really enjoyed the book and thought that it was a very well written piece. Once I had read the Avatar books, I reread the book and liked it even more.
German cover (Cross Cult reprint):
