As Revelation mentions, apocalyptic gathering engendering devastating destruction of Nature, primarily? (10)
I believe the answer is:
armageddon
'as revelation mentions' is the definition.
I can't tell whether this definition defines the answer.
'apocalyptic gathering engendering devastating destruction of nature primarily?' is the wordplay.
'apocalyptic' becomes 'arma' (I can't justify this - if you can you should give a lot more credence to this answer).
'primarily?' indicates taking the first letters (I've seen 'primarily' mean this).
The first letters of 'gathering engendering devastating destruction of nature' is 'geddon'.
'arma'+'geddon'='ARMAGEDDON'
Can you help me to learn more?
(Other definitions for armageddon that I've seen before include "final battle" , "complete disaster" , "Catastrophic conflict" , "large-scale fighting" , "bloody battle" .)