The kings of Israel are the kings of the 10 northern tribes which revolted and became a separate kingdom shortly after Solomon’s son, Rehoboam, became king. The northern tribes were also referred to as Ephraim because Ephraim was the predominant or leading tribe. https://www.gotquestions.org/tribe-of-Ephraim.html Kings of all Tribes Saul David …
Whosoever therefore shall confess me before men, him will I confess also before my Father which is in heaven. Matthew 10:32