Shi Feiyang had Bai Lingzi create a registry for each member of the Demon Clan under his command, recording their names, original forms, cultivation levels, and more.
Since paper can't be used underwater, they used merfolk silk instead.
The merfolk are capable of spinning threads and excel at weaving, so Shi Feiyang found a small basin and had the Merfolk King settle his people there: "From now on, this place shall be called Divine Merfolk Valley."
He also had the demons gather large rocks and colorful shells to help the merfolk build houses, using a few days of effort to construct a simple palace.
Underwater architecture has completely different considerations than surface construction, with the main concern on land being against gravity, while in water buoyancy is present. The foundations and pillars' primary function is to prevent the palace from being washed away by the sea rather than to support and prevent it from falling.