In your explorations of the Pyramid, you've learned that the Scorn were attempting to increase their power by using resonant runes stolen from the Lucent Brood in combination with worm larvae.
Based on the reports from those who first entered to defeat Rhulk, it seems these ritualistic experiments were a holdover from the plans of the disciple himself.
One Hidden agent goes so far as to speculate that the Scorn Caretaker was itself the result of a successful worm-fusion.
Whatever the Scorn know of Immaru's plans, it's enough to motivate them to enhance their power further in order to counter his moves.
The Pyramid should be continuously monitored, as the Scorn show no signs of slowing down. Visit the Pyramid regularly to clear the area.