First, the DRB precedes the KJV. The NT of DRB was first published in 1582 and the OT of the DRB was first published in 1609-1610. The KJV was first published in 1611. Both have been since revised several times.

Second, the DRB does not translate from the original Bible language of Hebrew (OT) and Greek (NT) but from the Clementine Latin text. Thus, the DRB is a translation of a translation. This Clementine text was formally published in 1592, and is a revision of that published by Jerome about 400 AD. The Clementine text was controversial and often shows many differences between from the original languages.

Isa 34:14 is one such difference. The Latin text is:

Et occurrent dæmonia onocentauris, et pilosus clamabit alter ad alterum ; ibi cubavit lamia, et invenit sibi requiem. = And demons and monsters shall meet, and the hairy ones shall cry out one to another, there hath the lamia lain down, and found rest for herself. (as translated by the DRB)

The Masoretic text of the Hebrew is:

וּפָגְשׁ֤וּ צִיִּים֙ אֶת־אִיִּ֔ים וְשָׂעִ֖יר עַל־רֵעֵ֣הוּ יִקְרָ֑א אַךְ־שָׁם֙ הִרְגִּ֣יעָה לִּילִ֔ית וּמָצְאָ֥ה לָ֖הּ מָנֹֽוחַ

= The desert creatures will meet with the wolves, The goat also will cry to its kind. Yes, the night-bird will settle there And will find herself a resting place. (NASB)

It is debatable whether demons are ever mentioned in the OT (in contrast to the Devil or Satan who appears several times). However, there are a few words that probably mean "demon":

• שֵׁד (shed) eg, Deut 32:17, Ps 106:37. The Latin & DRB translates this word as "devils" in both cases.
• שָׂעִיר (sa'iyr) meaning "hairy" which is rendered "demon" by some versions in Isa 34:14, 13:21, Lev 17:7, 2 Kings 23:8. In most cases it is simply translated as "male goat" or equivalent, eg, Gen 37:31, Lev 4:23, , 24, 9:3. Interestingly, Esau is described using this word in Gen 27:11, 23.

Therefore, if we include "devils" with "demons", the DRB uses the idea in other places as well. Further, "Satan is also mentioned in the DRB in Job 1:6, 2:1, 6, Zech 3:1, 2, etc.