I must say that I believe that this is a great question because from Divine Revelation, it appears that that is how God works.
20 For it is written in the book of Psalms,
‘Let his habitation become desolate, and let there be no one to live
in it’; and
‘His office let another take.’ - Ac 1:20 (RSVCE)
Having said that, there seem to be no evidence in Divine Revelation to indicate that that has happened. I say that because the war that broke out in heaven continues on earth.
The other information we get from Divine Revelation are the 3 out of 7 names of the Arch-Angels: Michael, Gabriel, and Raph′ael.
The seven are in the OT and the 7 appear in the book of Revelation. Given the gematria of the number 7 in Judaism, it appears that primeval serpent, who is called the Devil and Satan, clearly was NOT a member of the Mystic Seven.
Who will fill up the gaps in the ranks of the angels, of the angels who left their proper dwelling?
The Scotist doctrine on the motives of the Incarnation, it would seem, is incompatible with another opinion held by some old theologians, to wit, that men were created to fill up the gaps in the ranks of the angels. [cf. Devil | New Advent].
I do not find anything in Divine Revelation that says how the gaps will be filled.
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