Delio says:
Could you develop your idea a bit ? I'm not against it, but i'll need further explanations to make it work.
Crab and Crane have never been in any good relation, they literaly hate each other, especially since the Yasuki have deserted the ranks of the Crane.
Kaiu engineer is a great idea, and with the Yasuki spouse, you got a nice network to move with.
Hate is fine, adds to the drama. The idea I had is that I was traded to the Crane for assignment. Additional material (not stone or earth, but specialized items such as rope, compounds for mortar, special woods, etc.) is needed to repair the wall, material that the Crane have. In order to achieve the trade, they opted for the Yasuki patented trade as gifts. The Crane need this expertise in siege warfare. The Kaiu need these materials.
Longer story, grew up in the household of Yasuki Yashiki as parents dwelt there while administering and maintaining the Watchtower of the East. Fell for a Yasuki girl as children, and the matchmakers were encouraged to make it official.
As an adult, have spent time in the wall, at the watchtower, and the Black Crane Estates.