A cluster located in the Terminus Systems, the Eagle Nebula is a free-for-all colonization and resourcing prospect for multiple species. Humans, batarians, salarians, and hanar (with their drell servant-partners) all have sizeable stakes in the cluster. Mercenary factions with known activity here include Eclipse and the Blood Pack.
There are a number of hanar colonies known to orbit planets that are especially beautiful from orbit (none of these planets is aquatic, so most of the population remains in orbital modules).
Amun System: Sekhmet, Sobek, Anhur, Neith, Bast
Imir System: Osalri, Korlus, Quodis, Gregas
Malgus System: Uzin, Wrill, Flett
Relic System: Murky Water, Fitful Current, First Land, Island Wind, Rough Tide, Preying Mouth, Beach Thunder
Strabo System: Antigar, Jarrahe Station
Vrylor System: Osmadus
The mass relay for the cluster is located in the Imir System, which has one inhabited planet: Korlus. As such, control over Korlus would allow a force to more easily exert control over the relay, as they'd have a local base to return to. Therefore they could effectively exert control over the Eagle Nebula itself. This made the world a popular destination for mercenaries and would-be conquerors that wished to make the Eagle Nebula into their own personal domain, until the Reaper War, when a Cerberus incursion resulted in the accidental destruction of one of the comm. buoys connecting Korlus to the rest of the galaxy. The discrepancy was finally noted in 2189, and rectified. By this point, though, various factions were fighting for control of the planet. Many potential overlords have made an appearance; none has succeeded.
Modos Gomorrian: Here's one of those hopefuls.
The Eagle Campaign: Fighting underway in the nebula.