This is for ch 19 because 18 is basically Uchimura revealing how he tricked the thieves into taking fake Rose Marin then when the king was about to kill the pig he stopped the king.
The 'reveal'...if you can even call it, is that despite his nickname as Death's Merchant, the guy was actually among the first to risk his life in order to open new business routes into places like wartorn country or such, meaning he is more or less the center of a large business network that if he die would likely collapse and the resulting economic damage would even destroy Rampage Kingdom since its export is reliant on his trade route.
And those thieves were actually his children, or more specifically orphans that he picked up during his travels and raise as his own children then they decide to work for him when they grew up.
In fact Uchimura even entrust him with distribution of Rose Marin because with his massive trade network he can spread it further than what the demon king army can handle alone.
honestly the king should have seen it coming.
Then again the Chinese have been doing this exact same thing with US products and all the US government did, was bend over and take it.