I'm making this region mostly based on the Bible, but there will be nods to other parts of the geology, geography, zoology, etc.
For the grass starter, I decided to refer to the Tree of the Knowledge of Good and Evil, since it was one of the first two trees ever mentioned in the Bible, which caused Adam and Eve to stumble. I know tree designs aren't very canon to the Pokémon world, but I thought it was too important to leave out. Not only did I base it on the Tree, but also from the Tower of Babel, and the fallen nation of Babylon, which have a dark history in the Bible.
For the water starter, I based it on sheep, due to the significance of sheep in the Bible. From Psalm 23 about the Lord being our shepherd and leading us to still waters, to being a sheep without a shepherd, to separating the sheep from the goats, and the lambs that were offered as sacrifices. It was mostly inspired, however, on the first part: "The Lord is my shepherd…He leads me beside quiet waters." The starter begins as a sheep without a shepherd, naive to the world and clumsy in its footwork. When sheep see rapids, they get distracted by the current and get dizzy and tend to fall in. The evolution ends with a sheep who now acts more like a disciple. Similar to how King David was a shepherd and followed in the Lord's footsteps, or the disciples who picked up Jesus' work after His resurrection. Its name is another reference to Psalm 23, "Your rod and your staff, they comfort me;" a rod and staff being two tools used by shepherds to keep their flocks from harm (rods to protect and correct them, staffs to bring them out of sticky situations like the river currents).
For the fire starter, I based it on the serpent in the garden who sweet-talked Adam and Eve into eating of the Tree. It's a cunning creature that knows that water-type is strong against fire-type, so it convinces the water starter that the grass starter is safe to eat, and surely it won't die. I gave the beginning of the line legs to refer to the curse it gets later on when it says, "you will crawl on your belly and you will eat dust all the days of your life." So as it evolves, it loses another set of legs until it has no more. I also incorporated elements of the goat synonymous with the devil.
by EeIectro