...
The one thing that has been pointed out that I will concede, is that the game doesn't present a situation where MC is invited to enjoy another woman by the significant other of that woman, which might feel the approach towards that dynamic a bit unbalanced. (I agree that the Queen passing around a slave is a poor representation of that idea, albeit conceptually the same).
This however is not the gotcha moment you might think it was. It simply means we haven't gotten around to it yet, as we were busy establishing the factions and getting the different missions rolling. The encounter at the Oasis might have been a good moment to introduce that narrative, but that would have robbed Shani of het moment to shine.
I shall relinquish the soapbox now.
I guess you could say that the player has NOT yet been introduced to another male NPC with the same 'stature' or 'power' (probably not the best words) as the MC himself.
Omar is definitely not it. Igor don't have a woman that he can offer to friends. Mutants, Raiders and Zeta are led by women. Although, to a small degree you could say that
Fang did share
Mantis with MC,
Kyra practically hand over
Asha (her little sister) for MC's amusement, and
Queen Mernith shared her slave with MC in the pool scene.
Lord Abrax could potentially be the guy. He didn't invite
Zaton the first time they met at the Decayed 'base' though, I think because
Zaton has not 'proven' himself yet. Sure he was
Abrax protegee in the past and a god damn fine Desert Stalker too, but I mean in terms of 'allies' or 'friendly' instead of foe. I would think that no one would entertain their foes no matter how powerful they are

. Also, there is also the possibilty
Abrax is no longer practicing it (or he never did before) since he left Zetan and the Zetan way of life long time ago. It is a personal choice (to indulge in such practice) and not mandatory cultural practice, as I understand it.
The game can introduce other male (and female) NPCs to depict this culture explicitly for sure, or not (considering the game already has far too many NPCs

). Most certainly there will be players that will want these ('sharing') female NPCs to become actual LIs for MC although that will create conflict between MC and the male NPC.
One thing for sure, those who enjoy the 'sharing' scenes don't demand any hard evidence or proof of such culture, at least not that I am aware of

.
Anyway, just bring what you have cooking onto the table. Some will enjoy it, some will hate it, some just don't care. There is no way around that.
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My personal view about the whole kinks of Desert Stalker is that the DS Team had weaved the various kinks (avoidable) beautifully into the multiple stories in the game.
Just an example, the story with
Igor is mainly so that the MC can get
Katerina. The 'sharing' kink (reasonable and believable) was weaved into that story and players who enjoy it can choose that route and experience the expanded scenes. In the end, MC can get
Katerina regardless of the route. Okay, it is an oversimplification because players can choose to deny
Igor and/or reject
Katerina if they wish, so MC does not always gets
Katerina.
If 'sharing' kink is the theme or focus of the game in general, then surely
Igor is not mandatory because it can be just any male NPC or not just this particular story.
Other examples are 'Rough questionable sex' kink was weaved into the Raiders story, 'urination' kink into the Fairy introduction etc. I am not saying that each kink is unique or exclusive to a particular story either but rather the kinks that make sense are weaved into suitable stories in the game.
All that being said, power (to a certain degree) is in the hands of the players (being able to choose what they like or what to see/happen), but the ultimate power is in the hands of the developer, the DS Team (who make whatever types of contents of the game). So, who really wants that ultimate power, you just make your own game, where you dictates all the rules of engagement.