Cherethites/Kerethites seems to not be an actual tribal name, for it is a paronomasia, the Hebrew karat means to cut off. Ezekiel puts them in the same group as the Philistines that stand against God’s people and will be destroyed. So I will cut off the cut off ones.
. . . therefore thus says the Lord GOD, Behold, I will stretch out my hand against the Philistines, and I will cut off the Cherethites, and destroy the rest of the seacoast. Ezek. 25:16
Woe to you inhabitants of the seacoast, you nation of the Cherethites! The word of the LORD is against you, O Canaan, land of the Philistines; and I will destroy you till no inhabitant is left. Zeph. 2:5
What We Know
The Kerethites are not mentioned very often. When the Bible first introduces them they are in the Negev, which is a dessert in eastern Egypt that borders Modern Israel.
We had made a raid upon the Negeb of the Cherethites and upon that which belongs to Judah and upon the Negeb of Caleb; and we burned Ziklag with fire.” 1Sam. 30:14
They become a conquered people serving David.
. . . and Benaiah the son of Jehoiada was over the Cherethites and the Pelethites; and David’s sons were priests. 2Sam. 8:18
. . . and Benaiah the son of Jehoiada was over the Cherethites and the Pelethites; and David’s sons were the chief officials in the service of the king. 1Chr. 18:17
And all his servants passed by him; and all the Cherethites, and all the Pelethites, and all the six hundred Gittites who had followed him from Gath, passed on before the king. 2Sam. 15:18
These Kerethites make up part of David and Solomon’s MightyMen.
And there went out after Abishai, Joab and the Cherethites and the Pelethites, and all the mighty men; they went out from Jerusalem to pursue Sheba the son of Bichri. 2Sam. 20:7
Now Joab was in command of all the army of Israel; and Benaiah the son of Jehoiada was in command of the Cherethites and the Pelethites; 2Sam. 20:23
So Zadok the priest, Nathan the prophet, and Benaiah the son of Jehoiada, and the Cherethites and the Pelethites, went down and caused Solomon to ride on King David’s mule, and brought him to Gihon. 1Kings 1:38
. . . and the king has sent with him Zadok the priest, Nathan the prophet, and Benaiah the son of Jehoiada, and the Cherethites and the Pelethites; and they have caused him to ride on the king’s mule; 1Kings 1:44
FYI: There is possibility that the Carians were identical to the Cherethites. If this is the case, then it appears that these mercenaries were loyal to the house of David and supported Joash over Athaliah
But in the seventh year Jehoiada sent and brought the captains of the Carites and of the guards, and had them come to him in the house of the LORD; and he made a covenant with them and put them under oath in the house of the LORD, and he showed them the king’s son. 2Kings 11:4
And he took the captains, the Carites, the guards, and all the people of the land; and they brought the king down from the house of the LORD, marching through the gate of the guards to the king’s house. And he took his seat on the throne of the kings. 2Kings 11:19
So the question is, if they were loyal to the house of David why does Ezekiel’s prophecy but them in the same group as the Philistines? Especially since both groups had disappeared from the historic record. No one knows.