John Gill Commentary 1 Chronicles 12:20

"As he went to Ziklag, there fell to him of Manasseh, Adnah, and Jozabad, and Jediael, and Michael, and Jozabad, and Elihu, and Zillethai, captains of thousands that were of Manasseh." — 1 Chronicles 12:20 (ASV)

As he went to Ziklag, there fell to him of Manasseh
Others besides the former, who joined him when he went with the Philistines; these joined him when he was dismissed from them, and was returning to Ziklag: namely,

Adnah, and Jozabad, and Jediael, and Michael, and Jozabad, and Elihu,
and Zilthai, captains of the thousands that were of Manasseh
that tribe being, as the rest were, divided into hundreds and thousands; these were captains over the thousands of the militia of the tribe.