I'm a bit lost on this arc. Could some kind soul give me a summary, please?
I also remember (or I may have misunderstood), but didn't another High-human appear a few chapters ago? Or was it an NPC from an old PK player?
It was an NPC who knew Shin was a High-Human, there are only ~6 High-Humans mentioned in the story so far and they're all guild mates with Shin so it'd have been a huge deal if we met them since their considered godlike.
Quick recap because it's been a minute.
The NPC is passing down his sword which is a high-human made weapon, aka shin made it, but because it's ridiculously powerful and due to the local prestige it carries the two main family factions are squabbling over the rights to own it. The family shin is with (East) doesn't want to give it up because the NPC is their retainer and he should be allowed to pass it down to whomever he wishes, the other family (West) said it's unfair for them to keep it as they've owned if for many years.
The stories is basically playing a mock feudal japan with one being a war faction and the other being a more peaceful faction but the war faction has grown in strength recently and has less opposition from other families due to the call of unification. I don't recall if that's because they've vassalized those other families in the west or conquered them but that's cliff notes iirc.