The Three SistersThe three sisters, Water, Air, and Fire, based on the classical elements, are goddesses or semi-gods. They are all partly responsible for life to be born and sustained on the world. They have undefined set of powers, with vague limits.
Even though they have created some of the animals and creatures on Earth themselves, they are not always interested on their well being. Nor can they understand the lives of mortals the same way mortals would, and issues like morality can sometimes be hard to grasp for them. They often try to influence the lives of mortals for their own goals, but without realising they are themselves influenced by the mortals with ideas like religion.
Rebirth: Every time one of them dies, she will be reborn in a new form, with sometimes her memory lost. Her personality and agenda might be different from her previous incarnation. Fire might, for example, be uncaring of the Fish People in her current life, but when she's killed by Water, her attitude might be all different. The nature of their rebirth depends on the way they are killed. If Fire dies without reaching her goals, or feels that her death was greatly unjustified the more vile and angry her next incarnation will be. As Air dies mostly on the hands of her sister, always feeling persecuted, she will almost always be reborn scared and seeking solitude.
One of them dying and being reborn, might be synchronized with some big change in the world. This might be evolutionary change of Fishpeople learning to walk and starting to breath air instead of water, or a technological and cultural one, where the Fishpeople or other creatures learn to use electricity or so on. It might also be a natural catastrophy of sorts. Thus the rivalry might be part of natural progress in the world, a catalyst for the world to change.
Air on the other hand, is not destined to find anyone, but tries to escape her sisters and tries to live in solitude. Maybe she takes refuge with the mortals by pretending to be one of them, or maybe she tries to stay in a formless state trevelling high in the Air, or maybe she has taken an appearance of a less important animal.
Food: While the goddesses are immortal they still need to eat or their powers will start to drain. What they can eat to survive depends on their incarnation. In some cases, the only they could eat, might be the dead sister they are destined to kill.
WaterThe current incarnation of Water lives in the caves near the Fishtown. The cave has some old pillars, part of some old temple. Maybe it was a temple made by some old civilization for one of the sisters. She lives off the dead bodies of the Fishpeople, who burry their dead as a gift to her.
She hasn't left the caves in this incarnation too often, so she doesn't really know much about the Fishpeople, or atleast about their new modern technology. When her food supply suddenly stops she is forced to leave her caves however. She doesn't really want to see the fish people hurt, but she might also be indifferent if one of them is in danger. The choice is player's, she can decide, for example, to save Thomas.
None the less, she doesn't prefer violence, unless she is not given any other choice. Her powers are not particularly violent either. She can try to attack creatures that are very near water surface, but she's very powerless when out of water. She can however, turn into liquid water and travel through pipes or go through metal bars.
FireThe current incarnation of Fire is perhaps mostly concerned about escaping Water's teeth. She atleast partly remembers her previous life, and has made up her mind not to be eaten by Water again. She is taking refuge in the Fishtown, where she has created the Word. The Word is a collection of powerful prayers the entitle a lot of fire releated spells that can help and protect the user from danger. These might include healing prayers, or prayers of purity, or spells to create fire balls.
The Fishpeople have given her the title of Reverend, the Head Of the Church, as they have built their religion around the Word. Fire doesn't really care about the Fishpeople, but they might be helpful to her against Water. She doesn't have any conception of morality before entering the town, and doesn't really intend the Word as guide for mortals to how to live their lives. The Fishpeople, however, keep asking her for advice, and she's getting more and more annoyed with them. She might say the first thing that comes into her mind, no matter how harmful, just to get rid of the mortal.
AirNo-one knows what the current incarnation of Air looks like or what her powers are. She is most likely hiding somewhere from both Water and Fire. She is not seen in Water in any form.
EarthEarth is the mother lion of the Three Sisters. She's seen in the second chapter of Water, being imprisoned by the Fishpeople (without them knowing that she's a Goddess). Her powers are unknown, but she might be the planet itself, or the consciousness of it. She might not be immortal, but if she would die, the change on world would be a lot more catastrophical than the death and rebirth of one of the Three Sisters. Indeed, it might be cause the death of the whole planet.
Even though she is powerful enough to create the Three Sisters, she seems to be have imprisoned by the Fishpeople, even though maybe willingly. This might hint that she doesn't want to use her powers, and unlike the Three Sisters, she has an idea of what is good and what is wrong. When she meets Water in chapter two she warns her about the quest to find Fire being demeritous to her.
She doesn't reveal herself to Water or any of the Three Sisters in purpose, as she wants them to learn on their own rather than tell them how to behave. She didn't create her children to be rivarlies, but feels that it is necessary to allow them to fight and sort it out on their own.
FishpeopleThe Fishpeople, in their original Fish form, might have been created originally by Water. Maybe Water created them herself in her previous incarnation to maybe protect herself or as an army to attack Fire. They were still mostly fish like, although maybe slightly more evolved from the ones you can see in-game swimming around. However, Water in her current form does not remember creating them.
But Air, or her death, that caused them to evolve into air breathers, and to walk on ground. Thus Air become their second creator. The Fishpeople themselves still thought Water as their mother, and used to sacrifice their dead for her like the temple people before them.
However, when Fire died, igniting the creation of new technology, indrustial era with electricy, machines and motors, the Fishpeople changed again. This time Fire became their focus of worship, as she was not only responsible for their technology, but their new religion, the Word, as well. They had been following and worshipping Water for ages, but in her new incarnation Water had not cared or remember to command them, but only enjoyed their sacrifices.
In Fire they saw their new leader, even if she didn't want to lead them. They were originally created as servants, and perhaps, slaves, and it was still part of their nature to be obidient and have no mind of their own. Soon they started to listen for every word she said. They would follow her orders blindly, and if she would have commanded them all to jump of a cliff in her frustration with them, a lot of them would have surely done so.
Only an occasional few would fight against their nature, or perhaps from some kind of loyalty to Water, ignore Fire, and not think of her as their leader. It might also be releated to their status, or if it is fitting for them to serve Fire. Some might like the power the Word brings for them.
FishtownThe Fishtown is a large indrustial town rising from the sea, and seemingly the only piece of dry land in the area. Before the revolution of the indrustial era, the fishpeople were using a lot of wooden structures, some of that are still visible in the town. In the present day there's technology like phones and steam engines, and a lot more of the buildings are made of stones.
The Great HenriThe Great Henri was a folk hero of the Fishpeople. It is said that the foundation of the town was built by him over a thousand years ago. The legend exaggerates by saying that he used only his will power to rise it from the sea. He is perhaps the only thing close to a religion or myth, the Fishpeople have, other than the sacrifices to Water or the Word.
CrabThe crab people, or crabs, are the size-of-dog creatures living under the water surface. They have a weird fascination with garbage thrown into water and their favourite food is tacos.
Crab King is the leader of the crabs. In chapter 1 he's trying to commit suicide, because the Fishpeople have stopped throwing their garbage into the water and he is bored into tears with his life. Water can either promise to do quest to get the fish people to throw their garbage into the water, or find some tacos for him.