Jehoram son of Jehoshaphat.
Ahab and his wife Jezebel only had the two children, Ahaziah and his sister Athaliah, who was married to Jehoram the son of Jehoshaphat the King of Judah.
1 Kings 22: 51; In the 17/18th year of the reign of Jehoshaphat king of Judah, Ahaziah the son of Ahab became ruler of Israel, and reigned for 2 years, and then died after a fall from the balcony of his palace.
Jehoram son of Jehoshaphat and son-in-law of Ahab, then ruled Israel for 4 years, until the death of his father Jehoshaphat, he then ruled Judah also for 8 years, ruling Israel for 12 years, and for 8 of those 12 years, ruling both Judah and Israel from Samaria.
After receiving a terrible wound in a war with King Hazael of Syria, he returned to Jezreel to recover from his wound which had become infected, leaving his son Ahaziah and his wife Athaliah to rule in Jerusalem.
Ahaziah the Son of Athaliah the daughter of Ahab ruled in Jerusalem, for 1 year, before visiting his father in Jezreel, where they were attacked and both Killed by Jehu.
I have never met anyone of the Jewish faith, who accept that Jehoram the son of Jehoshaphat ruled Israel for 12 years. WHY?