The Aglevan system is an eleven planet system. Their habitable zone contains 4 planets, 2 of which share a co-orbital configuration. Aglevan II is where most of the life in the system resides. It has 2 uninhabitable moons. It has a heavier atmosphere with an extremely high humidity. To compensate, the major sentient species, calling themselves the Aglevan, have a gill and lung system to adapt to their wet weather and climate. Both planets function on .9 G, letting the Aglevan grow taller, and slender.
Its sister planet, on the same revolution is relatively close to Aglevan II. For several months in the year, the sister planet, Agleven III sits in the night sky like a third moon. The planet is a vast oceanic world, violent storms and quickly changing weather broil over its surface as the vastly different oceans mix and swirl.
No long in the development of the Aglevan, they colonized their sister planet, creating floating colonies and ports to harness the resources of their neighbor.