"We stand at the precipice of victory. There is but one final link that remains between Calus and the Pyramid, and we are ready to strike at it."

Eris bound Caiatl to the Crown of Sorrow and gave the empress as much of an edge as possible in her impending confrontation with Ghaul.

"However," Eris warns, "by my estimates, Calus has already infiltrated the paracausal matrix of the lunar Pyramid."
"The dark below groans and churns with excitement at this revelation. Emanations from the lunar Pyramid whisper a singular psychic demand to all who can perceive it: REJOICE."

Eris urges you to go and gather the necessary energy to complete the final ritual of severance, before Calus can wrest control of the Pyramid.