I don't think that's quite accurate.
Here's one other option. I think there are others:
Numbers 21:6 KJV — And the LORD sent fiery serpents among the people, and they bit the people; and much people of Israel died.
I didn't say that they were the only things that ever killed anyone and besides, the Bronze Surpent story is a picture of Christ where disobedience toward Moses (i.e. the law) results in death but looking upon the fiery serpent that God had Moses set on a pole, defeated that death. It's totally a picture of Christ being crucified as a sacrifice for sin, a process clearly laid out - guess where - in the law.
Numbers 21: 4 Then they journeyed from Mount Hor by the Way of the Red Sea, to go around the land of Edom; and the soul of the people became very discouraged on the way. 5 And the people spoke against God and against Moses: “Why have you brought us up out of Egypt to die in the wilderness? For there is no food and no water, and our soul loathes this worthless bread.” 6 So the Lord sent fiery serpents among the people, and they bit the people; and many of the people of Israel died.
7 Therefore the people came to Moses, and said, “We have sinned, for we have spoken against the Lord and against you; pray to the Lord that He take away the serpents from us.” So Moses prayed for the people.
8 Then the Lord said to Moses, “Make a fiery serpent, and set it on a pole; and it shall be that everyone who is bitten, when he looks at it, shall live.” 9 So Moses made a bronze serpent, and put it on a pole; and so it was, if a serpent had bitten anyone, when he looked at the bronze serpent, he lived.
Partaking of the Tree lead to death...
Genesis 2:17 but of the tree of the knowledge of good and evil you shall not eat, for in the day that you eat of it you shall surely die.”
The law came because of the offense at the Tree....
Romans 5:18 Therefore, as through one man’s offense judgment came to all men, resulting in condemnation, even so through one Man’s righteous act the free gift came to all men, resulting in justification of life. 19 For as by one man’s disobedience many were made sinners, so also by one Man’s obedience many will be made righteous. 20 Moreover the law entered that the offense might abound. But where sin abounded,...
Partaking of the law kills...
Romans 7:9 I was alive once without the law, but when the commandment came, sin revived and I died.
and as such has a ministry of death...
Romans 7:5 For when we were in the flesh, the sinful passions which were aroused by the law were at work in our members to bear fruit to death.
II Corinthians 3:7 But if the ministry of death, written and engraved on stones, was glorious, so that the children of Israel could not look steadily at the face of Moses because of the glory of his countenance, which glory was passing away, 8 how will the ministry of the Spirit not be more glorious?
Because of Christ the curse of the Tree is undone....
Romans 5:18 Therefore, as through one man’s offense judgment came to all men, resulting in condemnation, even so through one Man’s righteous act the free gift came to all men, resulting in justification of life. 19 For as by one man’s disobedience many were made sinners, so also by one Man’s obedience many will be made righteous.
Under Grace the Law is likewise undone...
Romans 4:4 Now to him who works, the wages are not counted as grace but as debt.
5 But to him who does not work but believes on Him who justifies the ungodly, his faith is accounted for righteousness, 6 just as David also describes the blessedness of the man to whom God imputes righteousness apart from works:
7 “Blessed are those whose lawless deeds are forgiven,
And whose sins are covered;
8 Blessed is the man to whom the Lord shall not impute sin.”
Galatians 5:2 Indeed I, Paul, say to you that if you become circumcised
*, Christ will profit you nothing.
* Circumcision, being a cutting off of the physical flesh is a symbol of the law which is a cutting off of "the flesh" (see Romans 7).