The future is a story that is told--shifting with each telling, adapting to the needs of the audience and the whims of the day. The end seems to change often, but the details less. It exists nowhere but on the fleeting wind carrying it from the visionary to the rapt attendee. Someday, it may be written down and preserved, but in so preserving, it will lose some of the vitality that made it magic.
The present is the teller of these tales, picking and choosing between the myriad visions whirling about in his head, discarding a hundred to find the time to write down one. The one that survives mourns for its lost brethren, but silently, in between the pages of the tale it has become.
Coming at it from the angle of Stories, I think Fate is ultimately tied to the concept of purpose. The Fate of a person, object, or institution is the reason it exists. In proper Stories, all things have a reason for being in the story. Within they story, once they have fulfilled their purpose, they either disappear or acquire a new purpose as a result of having changed. In general, then, one can either fulfill one's Fate or fight against it. If you don't like your Fate, you can change, but only by actively changing yourself. Your Fate is an aspect of what you are and how you behave, and fundamentally altering that, you can change what is you are capable of doing and will ultimately do in your existence. As such, Fate is a rather vague and nebulous thing which is hard for most beings to detect. In a way, it's a meta-language issue; you have a hard time seeing your own Fate because you're yourself. Others can often see it clearer, but whether or not they will or can tell you is another thing. Unlike some conceptualizations of Fate, I'm not seeing it as an eventual doom or even that related to destiny; it's really just the ultimate meaning and reason for your existence, which you can sculpt in a limited fashion if you truly apply yourself.
With respect to alterations in Prasinos, it could manifest as a clearer vision of his own purpose in creating a Chancel and Ennobling us. Physically, this could come about as something stereotypical, like the development of a third eye enabling clearer sight, or it could be a subtler change. He might shift colors somewhat, or, perhaps more appropriately, experience a change in texture. Perhaps the grass on his back will become filled with small insects which are continuously born in his mane and then make they way back, meandering to and fro but generally moving towards the rear until they reach they end of their span and their dry shells tumble down behind the great lion. Each insect is a possibility, a path to be taken, a moment that must be seized as it makes its inexorable way to its end, where it will fade into the mists of the past. Such realization of the Fate of all things would give him a better understanding of reality and thus be the perfect justification for buying off Degenerate.