If Dusknoir with the "Spectral Breach" Ability is already in play and then Fusion Strike Energy is attached to a Pokemon (either mine or my opponent's), does Fusion Strike Energy prevent "Spectral Breach" from affecting it, or does "Spectral Breach" disable Fusion Strike Energy's effects?
When Fusion Strike Energy gets attached to a Pokemon it prevents the effect of Spectral Breach, therefore providing every type of Energy and preventing all effects of your opponent's Abilities done to that Pokemon.
Source: TPCi Rules Team (2021-12-23)

Relevant cards

Note: All applicable cards may not be listed below.
SWSH4_71
SWSH4_71
SWSH8_244
SWSH8_244