User blog comment:Magma MK-II/Category Cleanup (continued)/@comment-26921356-20160406224333/@comment-366087-20160409204520

So, using the Compass Direction analogy, you can set out in ONE direction, then turn around to go the opposite direction. But you cannot go BOTH directions at the same time.

"Dissonant Serenity"—which does not exist in any officially recognized profession—would be the same way just going by the definitions of the two words. "Serenity" refers to a condition of peace, particularly peace of mind or spirit. "Dissonant/Dissonance" refers to a mental (or musical) state of Discord. Disharmony. Conflict.

A person can not be both in a state of Conflict AND Serenity at the same time. Not even with MPD/DID are the conditions simultaneously. Like walking the Compass Direction, each personality can only be one, or the other, but at different times.

I think what they want to mean is "serene despite surrounding chaos" using a fancy-sounding made-up and clinically incorrect phrase.

In addition, "Dissonant Serenity", if not an invention by TVTropes, is used extensively by them, and we are distancing ourselves from TVT terms as much as possible.