Is there a word, such as personified, but which can be applied to an object such as the sky? Something that would describe the sky to be mystery personified?
Best I can come up with at short notice would be to perhaps describe the sky as the embodiment of mystery. , or to say mystery manifested.
Technically I think the word would be "objectified", but because the word has negative connotations in popular use it would probably be better to use one of the other suggestions.