A look at how the death of Jesus affected the devil.
The letter to the Hebrews tells us that the devil had the power of death, but the death of Jesus brought the devil to nothing:
14 Since then the children have shared in flesh and blood, he also himself in the same way partook of the same, that through death he might bring to nothing him who had the power of death, that is, the devil,
The Bible helps us understand the devil by telling us that sin causes death:
12 Therefore as sin entered into the world through one man, and death through sin; so death passed to all men, because all sinned.
23 For the wages of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord.
15 Then the lust, when it has conceived, bears sin. The sin, when it is full grown, produces death.
The Bible helps us understand an aspect of the devil by telling us that the death of Jesus removes the effect of our sin:
29 The next day, he saw Jesus coming to him, and said, “Behold, the Lamb of God, who takes away the sin of the world!
26 or else he must have suffered often since the foundation of the world. But now once at the end of the ages, he has been revealed to put away sin by the sacrifice of himself.
5 You know that he was revealed to take away our sins, and no sin is in him.
We see that the death of Jesus removes the effects of sin - connecting the devil to sin.
We conclude that the devil refers to sin and its effects, which were brought to nothing by the death of Jesus Christ. The apostle John confirms this idea:
8 He who sins is of the devil, for the devil has been sinning from the beginning. To this end the Son of God was revealed: that he might destroy the works of the devil.