Essenus is a hydrogen-helium gas giant once famous for its fuel infrastructure. Its proximity to Palaven and well-developed antiproton plant made it an easy choice as the center of numerous fleet movements for Turian Hierarchy naval vessels alongside the impressive garrison once stationed there. It also made it an easy target for the Reapers.
The Reapers drove the turians off and destroyed all available machinery. After the Reapers moved on, a few volus ships moved in to scavenge the wreckage.
The Hierarchy hasn’t forgotten the planet's legacy, however, and Essenus has been the center of a committed initiative to rebuild the planet in its former image. Though its current output is nowhere near former levels, it’s still the Apien Crest’s most productive fuel depot.