Have you considered instead having a custom NPC with the dialogue package that is part of another faction like Vagrants? If the Shek Kingdom is set to coexist with that faction I think it may prevent them from intervening in a fight with the player. They may then intervene on the player's side though, which presents some balance issues...

Its a really cool concept, just I think as it stands now the guards joining the fight is a bit of a stretch on lore, so you should probably put a repetition limit on it so that there isn't an incident nearly every time you head into a Shek city. 48 hours or even a week might be for the best.

In the world of Kenshi, there is no race of flying ichthyanders with four arms. Two arms for the crossbow and the other two for the wings, but they need to be crafted. They live on islands and are the only ones who can mine marble from the bottom of the sea. Skeletons at this depth are flattened by pressure. Marble is needed for facing the buildings of nobles and faction leaders. Ichthyanders are in alliance with mermaids, but not with Disney mutants with a tail, but with Slavic slender legs.
Kenshi - Developer Toolkit [SHIFT]+[F12] https://www.youtube.com/watch?v=Y0Jv_Jvm0kw&t=2s
you can build an impregnable city without crooked walls anywhere in the world, including in the sea using primitive terraforming.

@Carmelo Yes, that is supposed to happen. Most of the time when you start a fight in a Shek town , the guards join in. You are not expected to win this duel unless your character (s) is very op. But keep in mind defeating multiple guards will worsen relations too. After defeating the young punk, you could run from the other guards but you will have to run for a while. I could possibly change the AI of the Shek guards but that would change them for all the Shek towns and could leave the town vulnerable to other NPC attacks since the guards wouldn't be responding to threats properly.

i get attacked by shek guards once i accept a duel

thank you :)

thats a pretty cool encounter