Aplaima

Aplaima, also known as Devouring Rain, or simply acid rain, is found along the inner southwestern side of the Katorus Peaks in the Jatthirae Empire. The acid that falls from the sky is an integral part of the Halus, as it causes wood-skin Hethaskae.
Legend has it that when Ahegaalwa and Umaruq killed one another, their blood and tears mixed and formed the Idomarth Sea, but a part of Ahegaalwa found its way to the Katorus Peaks, and this Abyssian power continues to corrupt the land, causing acid rain to fall endlessly across an unreachable mountain range.
Wethosis and the lands beyond are ever-shrouded in bleak billowing clouds that rain Aplaima down on the lands. There are plants and animals that have adapted to the devouring rains, and the people who live here use the fibers, leaves, and hides to protect themselves from the rain. Heavy cloaks and hoods are common, and armour is designed to let the rain run off before it has enough time to seriously damage anything. It is punishable by death to become Halus without the appropriate permissions.
Aplaima itself is also has a few other uses, such as skincare, medicine, chemistry, and warfare, and it can also be burned in special lamps to give off a distinct greenish light and a pungent, overwhelming aroma. This is usually done in commemoration of royalty and nobility in the Jatthirae Empire.