History of Criticality

Overview

Criticality is the thirteenth mission of The Edge of Fate campaign (per Destinypedia), set at the Aionian Campus reactor on Kepler. The reactor threatens to melt down, which would destroy Kepler and feed the singularity. It follows Quarantine and precedes The Message. Characters: Ikora Rey, The Drifter, Lodi, Orin and your Ghost. Ikora declares she will control her own destiny rather than be manipulated by The Nine.

Sources disagree on the culprit: Destinypedia says Vex saboteurs (Nessian Schism), while the in-game description names House of Exile saboteurs.

Walkthrough

1. A 6-minute "Time to Criticality" timer runs; enemy kills drop motes that add 10 seconds each, so keep fighting.
2. Use the Relocator Cannon on rotating satellites to open portals forward.
3. At each of three coolant pumps, destroy three Rosetta Disruptors guarded by signal cubes (some need Matterspark), then restart the pump. Mattermorph fills gaps; Matterspark climbs and charges.
4. Boss: Eulochus, Fissile Mind, a Hydra in a Darkness Zone. At half health its shield returns: destroy the three Disruptors, go Matterspark, collect Arc charges to Supercharge, and use it on the Matterspark-vulnerable enemies to break the barrier.

The Critical Moment

The triumph The Critical Moment asks you to complete Criticality on Fabled difficulty in under 10 minutes (a light.gg search snippet says Fabled or higher). It is part of the Fated Weapon seal but guides say it can be skipped, since only 24 of 29 triumphs are needed. Variants: Mission: Criticality, Fabled Mission: Criticality, Mythic Mission: Criticality.