The core premise is a good one. I'm uncertain whether it's been used before, though John Ringo uses something similar in his Posleen series. The writing is generally professional grade, though there are a few clinkers in the dialogue. But there are some problems in timing, characterization, and the overall theme, especially the way you chose to end the novel.
The opening is a good example of "in medias res" structure. It shows us Jadeth as a grizzled veteran who, if he's not bursting with pride over his occupation, at the least he's not ashamed of it. He knows himself well enough to know what he's good for, and to know the limits to which he can aspire.
However, we get into jags of timing as soon as Jadeth comes into contact with Ilyan's little group. Ilyan is too forthcoming too quickly. He's too intelligent, and knows far too much, to be as candid as he was with Jadeth, who might have been anyone from anywhere. Of course, that does underline the importance of Jadeth's later role as security chief. Maiga's hostility toward Jadeth isn't adequately grounded; she has no real reason to resent him...and she doesn't distrust him nearly enough.
Now, you could say that Ilyan's whole raison d'etre is exemplified in his candor toward Jadeth, but as an intelligence analyst he would have had caution and suspicion inculcated into his persona very early in his training. (I've "done time" in that community, so I know whereof I speak.) As for Maiga, we don't get enough background on her to grasp her motivations, her overall character, her attachment to Ilyan, her antipathy toward Jadeth, or her solicitude toward Tesla.
Tesla -- I do hope the ghost of Nikola Tesla, one of Mankind's great geniuses, doesn't mind your appropriation of his name -- is similarly too thin for his role. You depict him as a whiner, a weakling, and something of a coward. All very well...but the clash against where he is, what he's doing, and the risks he's elected to share with Ilyan is rather stark. There was a way to rationalize his choice to follow Ilyan on his campaign, but I shan't recommend it; it carries a lot of baggage most readers would prefer that you not tote along.
There are parts of the story in which you depict Jadeth as almost feminine. I don't think that was wise. But then, there are parts of the story in which you made me wonder if Ilyan is bisexual...which would have fit well with the characterization path for Tesla that I'm loath to recommend.
The ending of the novel, though striking and dramatic, is likely to leave a bad taste in many readers' mouths. But then, having depicted mankind as a mercenary species, and having depicted Jadeth as something akin to an avenging angel, perhaps you had no better way to conclude it. I'll have to put this on the shelf alongside various other dystopian and inevitable-damnation-and-doom conceptions. But there's no question that it is original.
1. Watch out for exclamation points. Editors call them "screamers." 95% of the time they're a bad mistake.
2. There are some typos and misspellings -- and no, I'm NOT talking about the use of British spelling.
3. No one determined to keep his captive alive would use electrical torture in a metal cage. The risk of death is far too great.
Now, I'm fully aware that I'm the toughest reviewer on SmashWords, so I'm going to do the fair thing and measure your offering against other SmashWords SF novels. Therefore, you get full marks. But I hope you'll give some thought to the observations above. You display considerable writing talent in this book; some attention to good timing and consistent characterization would make you one of modern SF's stars. Also, I hope you'll give your readers more of a reason to cheer for Mankind in future novels; there wasn't much of one here!
(review of free book)