Angels populated Paul's world in a lively way. Contrary to modern popular assumptions, angels for Paul were not always good. They could be evil and malicious or simply morally ambiguous. There certainly are "good" angels in Paul's world (2 Cor 11:14; Gal 1:8; 4:14), and certainly also "bad" angels. 1 Corinthians 6:3 mentions that "we" (presumably Paul and other followers of Jesus) will "judge" angels, implying that there are angels who are criminal. If Paul's reference to the "thorn in the flesh" that tortures him is to an "angel of Satan" (2 Cor 12:7), which I take to be the case, and not just a metaphorical "messenger of Satan," we would have here a satanic angel as Paul's tormentor.
Some scholars believe that the phrase "because of the angels" in 1 Cor 11:10 is a reference to angels who may threaten women, perhaps sexually. Some scholars take Gal 3:19 to teach that angels were those who gave the law to Moses, rather than God himself. That text, if interpreted in light of Acts 7:53, may imply a less than benevolent, if not downright negative, view of their activity, given what Paul says about the intervention of the law elsewhere in Galatians. Finally, if one takes "the rulers of this age" in 1 Cor 2:6 and 8, who did not understand Gods mystery and therefore "crucified the lord of glory," to be a reference to angels (note that αρχαι are coupled with "angels" in Rom 8:38), this would certainly represent a reference to evil angels.
Dale B Martin, "When Did Angels Becomes Demons?" JBL 129, 2010, 657-77
Let me know what you think, :-)