The idea of paying 10 points for combat maneuvers not otherwise available, rather than paying equal to your STR (or multiples thereof), actually first appeared in Justice Inc. with its Boxing skill. Aaron Allston, of course, was one of the authors of JI, but I have no idea if Boxing came from him or one of his co-authors. Danger International certainly expanded upon that basic idea and led to the further developments as noted.
(The earlier Espionage followed the Champions model, but did add the ability to buy limited subsets of martial maneuvers for a fraction of the normal full STR cost, with these subsets defined as specific martial art styles.)
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