The only remaining Orokin Towers are hidden here. The Grineer patrol this area to prevent Tenno incursion.
Mercury is the first planet accessible to players, beginning with the mission Terminus.
The Grineer are the controlling faction on this planet.
The vital target of the planet is Captain Vor, who is located in the mission Tolstoj and has a chance to drop blueprints for the Cronus longsword and his personal sidearm, the Seer. He also has a higher than average chance to drop Morphics.
Grineer missions list does not apply to the survival mission.
In Update 11, though the Infested may not have dominant sector to fill can still appear as a raid faction.