The Sun Tzu ficcione

The premise of Sun Tzu's The Art of Espionage, a prequel writen to cash in on the runaway success of The Art of War, is that though the world of Espionage obeys the rules of Heaven, the life force of the individual spy is, a priori, out of balance.

A posteriori, how they end up is governed by which principle holds sway within them. Too much yin & the spy may be consumed by elements of self-destruction, display a subconscious desire to be outed, manifest it through actions such as dressing up as Gerard Depardieu in drag & living their life entirely in the dark. Too much yang & they become spy-hunter, keyhole peeper, closet cannibal, turning on their own, seeing them as enemy equal to those on the opposing side.

It's a precursor to the classic predator / prey model later postulated by both Lotka & Volterra, with the ratio of yin to yang determining who is x & y in the differentiated equation. But this is a finite model with an endpoint of zero. Too much egocentricity, too much paranoia. It does not stop when all known spies have been consumed; there must be others out there. Trust no-one, not even oneself. Eliminate them all.