Event Interference

Phenomenon Intervention (事象干渉) is an ability primarily possessed by Observers. It allows them to Observe a phenomena or existence and predicate an individual's own existence. Phenomenon Intervention allows one to also re-write discreet pieces of a target's past actions in order to help influence the reality of the present time. Phenomenon Intervention can actually be undone by the Manifestation Demolition Blade: Kusanagi.

If it cannot be determined if an individual actually “exists” or not, performing a Phenomenon Intervention becomes extremely difficult, if not impossible.

Takamagahara used an extortionate amount of Phenomenon Intervention during the Continuum Shift, using the scattershot event to pick-and-choose which timeline they favored when getting closer to the Azure; this stopped when Hades Izanami seized control over the AIs.

Certain characters are capable of resisting it to some extent, such as those that are outside of the Kotowari, like Valkenhayn, and to an even greater degree, those that wield the Power of Order, such as Hakumen and Jin Kisaragi. However, it does not include environmental alterations.