Water Layer

Salt water, fresh water, bubbling water, sweet water, and even drinkable liquid air, you can find all sorts of water substances in the water layer. The ecosystem here is fascinating not only because the majority of the layer is in an aqueous form, but the diversity of nutrition and resources the water itself is capable of generating. The water here is not just your standard ‘H2O’, but something more lively, more complex, and even a bit ‘metaphysical’.
Nobody knows exactly how the water layer functions. The depth of these ponds, lakes, rivers, and oceans, is beyond research and study. It is impossible to dwell deep into them because of the lack of understanding of it, but it is also impossible to gather knowledge of the water without dwelling on it. What we do know is that the layer has given birth to powerful races of aquatic creatures and all kinds of prosperous hydrophones, meaning the healthiness of the ecosystem is not at all affected by the lack of land and the resources which would traditionally be perceived as "only accessible on land".
The creatures living here are natural swimmers, as you probably already imagined. They are suitable to live in the water and enjoy being surrounded by it. The abundance of resources in this layer is enough for everybody, so there are rarely any conflicts over resources taking place at the water layer. Besides, nowadays the two races – the sharks and the hardshell prefer to occupy different parts of the water layer, leaving them with less chance of contact.
The shark race is a personification of provocative aggression. They love picking fights with whoever comes into their sight. Their sharp teeth suggest extreme lethal offensive capability and their fins allow them to perform high-speed manoeuvres underwater. However, most of the other creatures stay far away from them because of the aura of intimidation undisguisedly emitted by the sharks. So, the sharks value their "play time" with their prey as a supreme form of entertainment, and sometimes they even have to fight each other over a chance of predation. You better keep your senses sharp as you wander into the water layer, and if your instinct tells you to stay away from certain areas, it’s in your best interest to trust that precaution. You don’t want to become tonight’s entertainment for the sharks.
The hardshell race lives on the sandy beaches or shorelines. Sometimes they bathe in the water, but most of the time they prefer lying on the dry sand and enjoying their moments of leisure. It is clear that the ‘hardshell’ carried by each member of the hardshell race was not a natural feature but a result of evolutional adaptations. Maybe it’s because of the menacing sharp-teeth neighbours, the hardshells decided to find themselves ‘shields’ as a countermeasure towards the ‘spears’. The method is quite effective and has protected the race from shark attacks. But please don’t underestimate the combat abilities of these shield bearers. If you happen to see a toothless shark, it might be because of a full-power bash from a hardshell.