A large stone bridge crosses into Froghaven from the mountain next to it. There—like the rest of the perimeter of Froghaven—Frog Riders (their elite soldiers) stand guard in the massive trees of the forest.
Froghaven was formed around a massive crater created during the Great Battle. Over time it filled with water and became the lake at the center of Froghaven. Often referred to as "the Pond", the lake's magic enriched waters have created the tropical environment of the area as well as mutated most things that live there.
The trees are massive in height and diameter. Mimic vines—animated vines that feed off the life force of animals—are common. Many of the creatures living there are larger in size (like the frogs which are the size of a small horse) or have other unusual characteristics.
The Branchers are the only race that can live in Froghaven more than a few days. Because their bodies are not affected by magic they are not changed by their surroundings. Other races—and animals (not from Froghaven) that cross into the forest—begin to mutate and eventually die. The name Brancher is derived from the fact that they live in the tops of the massive trees of Froghaven.
There are two animal exceptions to the effects of the magic of Froghaven. The unicorn and deer are the only animals not of Froghaven that can enter and leave without being affected. Unicorns are magical creatures protected by the magic in their horn. Deer are the opposite of unicorns and, like the Branchers, are completely immune to the effects of magic.
There are four villages in Froghaven—one on each side of the massive forest (north, south, east and west). The villages have been created over the centuries by weaving/training the branches of the live plants into roadways, floors, roofs, etc. The largest village is near the stone bridge into Froghaven and is the capital. The Branchers welcome most anyone into Froghaven, but are strong on ceremony. If someone enters their woods without first visiting the king, they will be escorted out of Froghaven.
Below the waters of the Pond, live the Meremi. A variation of Brancher, they have webbed hands and fins flowing from their feet. They breathe water, but can survive for a few hours in the air. The Meremi do not welcome visitors, but will tolerate those accompanied by Branchers.
If your party of adventurers have a mage/magic user/wizard the game master can at their discretion give the skill "create breathe water potion" to them. Though this uses magic to create, it is mostly a learned skill mixing the right ingredients. The most important ingredient is the purple flower of the mimics that grow at the edge of the Pond. With the skill, the wizard has a 70% chance of getting the potion right (only one way to test if it works—attempt to breathe water). If unsuccessful they will have to start over with new ingredients. The potion is only good for a few hours after it is created. Once taken, water is transformed into air as it enters the adventurer's mouth. The effects last for 1D6 + 2 hours. When the mage takes their first breath underwater they will know about how long it will last.