Antonyms of downfall :
rise, advancement, development, evolution, growth, blossoming, flourishing, flowering, renewal, restoration, revitalization, heightening, accretion, accrual, addendum, addition, augmentation, boost, enhancement, gain, increase, increment, raise, supplement, ascent, upswing, advance, headway, progress, flower, heyday, prime, aggrandizement, exaltation, up, drizzle, mist, mizzle, scud, spit, sprinkle.
Examples of usage:
The clay surface held water, and after each downfall the pools would be higher, and the contour of the little region altered. "Edge of the Jungle", William Beebe.
There was a great pause, for none of us, when he did appear in sight, could shout over the downfall of so merciful a conqueror. "The Scottish Chiefs", Jane Porter.
We could tell a number of such stories where we feel confident that a very large family on very small means is largely to blame for the downfall of the older daughters. "Commercialized Prostitution in New York City", George Jackson Kneeland.