Volcania
Volcania is the name of an underwater volcanic island chain in the middle of Half Ocean. It is home to only a handful of species, as this dangerous environment is rendered inhospitable for most, due to the burning temperatures which can exceed a hundred degrees Celsius at best, even in the open waters. The volcanoes can exceed a thousand degrees Celsius, a temperature that even volcanic eusteans are not accustomed to.
Geography
The rocky geography of this environment creates lots of holes, which have erupted with magma at some point in time, creating large volcanoes. There are large cave systems below the volcanoes, which can actually enter the volcanoes near the base of them, and occasionally, when the volcanoes erupt, magma spews out through these caves to the sea floor.
Magma that is so hot, water cannot cool it, flows along the seabed. Some magical properties that people cannot explain allows the magma to flow right next to water without a reaction happening, which makes the environment more dangerous, but all the more beautiful seeing glowing red rivers along the sea bed.
Ecosystem
The few creatures that live here include small sea slugs. These slugs feed on the micro-organisms that also live here, and also feeds on the few plant species that live here. The only sapient species that live here, the Volcanic Eusteans, also feed on the plants and the sea slugs. They have constructed their homes out of the volcanic rocks, the heat from the rocks allows them to "mold" together the rocks, creating small houses out of the seabed.
Natural Resources
The volcanic rocks that make up the sea bed are valuable for volcanic eusteans, they constructed the entire village of Volcara out of these burning rocks. There are also some rare minerals that are found deep underneath Volcania, which can be accessed through the cave systems.
Underwater volcanoes are so cool- you should talk about the rare minerals that can be found in this region!
Smart! There'd definitely be lots there ^-^