Lamannia

Lamannia, the Twilight Forest, embodies nature, untapped and untameable. It's filled with all kinds of plants, animals, and magical creatures. It is often depicted as a realm of colossal trees, with beasts of incredible size roaming these giant forests. This forest is only one of the facets of Lamannia, however. Lamannia is the plane of nature, and every natural environment is represented within the layers of the plane. Other planes might feature similar environments to Lamannia, but in those planes the environment is the background for the concept that the plane embodies. In Lamannia, the environment itself is the concept, it is the point.
Lamannia lies closest to the Material Plane, and some planar scholars believe that it may have served as the blueprint for the material plane. These same scholars believe that Eberron is infused with the power of Lamannia, and that those who wield primal magic are actually manipulating this essence. Perhaps reinforcing this idea, druids that travel to Lamannia are often overwhelmed by the sheer natural presence of the plane. Travel to Lamannia is relatively easy, anyone traveling through unspoiled nature might find themselves there.
Lamannia is a reflection of the natural world, broken down into it's defining concepts. The air is clean and free of any form of pollution, and the water is clear and fresh. The whole plane is suffused with life, and this includes the environment itself. Most of the elementals used in elemental binding come from Lamannia, a realm where any stone could be an earth elemental. Flora and fauna are almost always in peak physical condition, hearty and healthy. This effect is so powerful that it makes it extremely difficult to contaminate the environment, food and drink is purified when it enters the plane, and natural materials like stone and wood are much more durable. Lamannia will not be tamed, and this applies to the inhabitants as well, the beasts and elementals of Lamannia cannot be magically charmed or influenced whilst they remain in Lamannia.
Most of the creatures that inhabit Lamannia are beasts, like you would find on the material plane, though they tend to larger and healthier. Then there are megafauna, gigantic beasts such as the Roc or Purple Worm, or gigantic versions of otherwise mundane animals like a wolf or a bear. Any natural creature can be found within their respective environments in Lamannia, and some scholars argue that it is actually a species presence in Lamannia that qualifies it to be considered "natural" in the first place. Most of these animals are no more intelligent than on the material plane, and behave as expected, but some have been noted to have humanoid levels of intelligence.
After the beasts, the most common creatures that inhabit Lamannia are elementals. Lamannia's elementals are the pure, primordial essence of the elements, unburdened by thoughts or desires as we would understand them. A fire elemental from Lamannia only wishes to express it's element, it just wants to burn. These elementals can come in a wide array of sizes and shapes, from tiny motes of elemental energy to staggering leviathans such as the Elder Tempest in the First Storm.
During the Silver Crusade, many lycanthropes fled to Lamannia to escape persecution, revealing a peculiar effect of the plane on them. For as long as they remain in Lamannia, lycanthropes cannot spread their curse to anyone other than their offspring, and the unnatural behavioural changes caused by lycanthropy are suppressed. At the same time, their primal instincts are amplified, a werewolf in Lamannia remains a predator, but they aren't driven to cruelty, they are a natural predator and remain in control of themselves. Communities of lycanthropes have appeared throughout the plane, scattered across the layers, and most can trace their origins back to the Silver Crusade.
Unlike most planes, Lamannia has no celestials or fiends, it has no need of them. There is possibly still a greater power guiding the plane, however, as explorers have reported a feeling of being watched, and attempts to despoil the natural environment are met with attacks by megafauna and elementals, or simply vicious weather. The shifters of the Eldeen Reaches believe that the moon Olarune is the consciousness of the plane, and that it guides events to ensure nature remains unspoiled.

Type

Dimensional plane