The author of the original novel talking about the history of the area and Le Gendre’s relationship with a powerful family in Hengchun, and a key figure of that family called Tiunn Miya (張棉仔) later renamed Tiunn Kongtshing (張光清).
https://www.youtube.com/watch?v=yIQ2CdIxepM
The talk is diglossic in Taigi and Mandarin.
The gist of it is that Miya belongs to the Makatao tribe, which has more interactions with Han Chinese by then. Miya was Le Gendre’s guide during the Rover incident, and he fulfilled that role for the 7 later visits Le Gendre made to this island.
Le Gendre basically instigated the later Japanese Mudan incident, which was a clone of the Rover incident. Mudan incident technically happened on the East Coast, however, in preparation for that incident, Le Gendre landed on the West coast because he needed to find Miya.
So despite the fact that since the US and UK both opposed the Japanese invasion of Taiwan, and the US arrested Le Gendre in Shanghai to prevent him from further assisting the Japanese, the Japanese troops still landed on the West coast, where Miya lives, gained his support to invade Mudan and used his house as their base.
Miya and many aboriginals friendly to Le Gendre helped the Japanese throughout their campaign, but when Japan signed a treaty with Qing afterwards, Japan simply ceded away their territory to Qing for them.
So in fear of Qing retribution, Miya and many other aboriginals adopted Han names, and hastened their own Sinitization. They also donated money to build a Qing fort in Hengchun to defend against other aboriginals.
In the end, the only clue left of the Zhang family’s Makatao past was a Makatao totem hidden in their Minnan styled family house.