Can Chained Devils in Ramaḍān Still Cause Harm?
Imām Ibn Taimiyyah, may Allāh have mercy on him, said:
The devils are put in chains [in Ramaḍān], so their strength and their actions are weakened as a result of their having been put in chains, and they’re not able to do, during Ramaḍān, what they’re used to doing in other than it.
He [ﷺ] didn’t say they are killed or that they die [in Ramaḍān]; instead, he said, “They’re put in chains.” One who’s been put in chains from among devils might still cause harm, but this is less or weaker than it would be during other than Ramaḍān. And then that’s relative to how perfect [a person’s] fast is or imperfect—one whose fast is perfect keeps the devil away to a degree that a [person whose] fast is imperfect cannot.
Majmūʿ Al-Fatāwá, vol. 25, p. 246.