This is what the Lu Family did not want to see.
Merfolk are creatures of myth, and once the news got out, there were surely many in the world who couldn't sit still—not because the merfolk were born beautiful, but because they were rare and... deified.
Human desires are endless. The poor want to be rich, the rich seek power, and those with power and wealth start to desire long-lasting enjoyment.
Longevity, immortality.
When a unique treasure of the world was exposed, it was bound to cause a frenzy of grabbing. Ginseng, because of its health benefits, can be auctioned for millions, so what more for a unique merfolk?
The wealthier, the more powerful one is, the more they fear aging and dread death. Merfolk are treasures all over; even their fallen tears turn into priceless pearls. The reason for the extinction of merfolk is merely their association with immortality.