恐るべき 事態に なりうるがため、 子細を 伝えることはできぬ。
The context is that I'm talking to a wizard in the game who happens to know something about my future.
Currently, I am trying to figure the exact construction/meaning of なりうるがため and so I far can guess that the sentence means something like I can't tell you the circumstances of your future, otherwise an awful event might happen.
But I can't wrap my head around what なりうるがため exactly is in it's construction.