It also fits with the overall theme of SoC; that power ultimately corrupts people.
Well... The center idea is about corruption or at least demonstrate that the willing of being good or evil is in everybody independently of their nature... But I think there's is another obfuscated theme, it's around the idea of hypocrisy... Since the beginning Rowan have some kind of remorse about being treated low independently of whatever he could help, achieved as general and member of the six heroes, achieved as commander and administrator or the twins, as husband...
But not only Rowan, near every character is around this idea at some extend:
Andras push his soldiers as Rowan as well but for people like Alexia when he wanted sex he expected for them to submit willingly to him, WTF?!, he could treat them as well as he does with Rowan and the soldiers but no, for them he's soft. In other annoyingly matters, he can comply to the orc villages needs if they swear loyalty...
Jezera's have the problem to like to be as civilized as those who are in charged, planning, plotting, dealing and diplomacy, but she offers between little and nothing while she doesn't reserve at all to make an example of force. I remember that she planned to threat using kids but she make assure to Rowan that even if the answer is no those kids will not be harmed, WTF?!...
Alexia... I hate this character... if you play to the loyal route, she by any reason isn't willing to sacrifice herself for Rowan meanwhile her husband (in the most loyal and boring route ever without NTR nor voyeurism nor cheating at all) little by little lose a piece of himself, of whatever he could ever think of himself and while he question his own moral... By playing corruption's path it doesn't matter how many cocks and cum she had passed to flavor, she will demand loyalty to her husband.
Helayna is a special case, when she recovers, whatever thoughts she had concerning to help the world against the threat Bloodmeen represent, just fall in nothing if Rowan declare his love for her, for Helayna being in hell but with Rowan as her lover is in a literal sense being in a paradise, a dream come true...
X'zaralt is another special case... Being interest in love and how others experiment it meanwhile being a watcher, now she desire to be participant or at least experiment the same love as much as possible with the test subjects she's studying. Being so blind that she now have a Rowan's spy under her nose...
Shaya is a very special case... After being encounter suspicious by Rowan in his investigation and curiosity, her trying to avoid-counter him she ended accepting him, to be more openly to him (in more than a sense)... Even after doing it can compromise her loyalty and put her in risk by confide in Rowan, something that could be a grave mistake if your overall regular job is being an spy (well, the Head of the Intelligence in Bloodmeen).
Liurial The Elf... This poor thing... It doesn't matter how good Rowan could try his best to make her a functional independent individual person, she still rely on him and willingly to submit in any form possible, because for her isn't a matter enough of being safe under the wing of a figure of authority, she desire this figure and she will even teach to her ideal figure of authority how she likes to be submitted... Even after abandon her group, the second in command for her she considered not worthy to serve because aspire to be as her dead master who committed grave mistakes... She's like a slave who doesn't want to be free but under a master, it doesn't matter how capable and prepared she could be... Poor thing...