Short answers, pulled from the story.
The Pali Canon translates sabbe sankhara anicca to all conditioned things are impermanent. This statement appears alongside two other essential characteristics of existence in Buddhist teaching known as dukkha and anatta.
Buddha expounded this no-soul doctrine in his second sermon to followers. The belief in a self over five skandhas or heaps is illusory and causes suffering.
These five components include body feelings perceptions impulses and consciousness. Individual persons consist entirely of these five changing elements without any underlying core.
Suffering from change usually stems not from the event itself but from clinging to pleasant experiences. Clinging to the idea of a fixed identity generates pain while recognizing fluidity brings clarity.
Anicca stands in contrast to Nibbana described as the only reality that knows no change decay or death. Nothing lasts and everything decays across all realms including deva god realms and naraka hell realms.