Ikora has given you a full briefing about the object that fell to Nessus. The Vanguard has taken to calling it the Echo.
"Thousands of civilizations across the universe, all visited by the Black Fleet," Ikora says gravely. "Memories from the victims of the Pyramids, held by the Darkness, then coalesced by the Light into artifacts as sharp and fatal as their pain."
"That's where this Echo came from," she says. "At least, that's our theory."
"My Hidden will keep searching for whatever answers the Witness's death can give us," Ikora assures you. "Hopefully they number more than the questions it left behind."
As Ikora searches for clues to the Echo's purpose, you must explore the depths of Nessus. "Massive amounts of radiolaria have been diverted beneath the planet's crust," Ikora warns.
"We need to find out what the Vex are building there."