Developer The Dark Watcher on specifics of a Rikti World Invasion: 1 "During the second phase of the invasion, the Rikti check to see if more of their Invaders are required every 6 seconds. The Rikti find out how many Invaders are currently on the ground. If that number is less than 100 and less than 3 times the number of players in the zone, the drop ships look for likely places to teleport more Invaders. Then they count the number of players within 30ft of the target and this number is used as the current Human Threat in the area for this target.