King Ahab is arguably the most evil king of the Northern Ten Tribes of Israel. He was the first Israelite king to marry a heathen (non-Israel) woman, the beautiful but devilish Jezebel. Together they became one of the most sinful couples in Biblical history. Ahab built an altar, in the capital city of Samaria, to his wife's pagan god.
Ahab, aided by Jezebel, helped lead the people into idolatry and set the stage for the nation's captivity that would later occur. Elijah the Prophet confronted him several times for his bad behavior (see 1Kings 17 - 18).
Jezebel not only fed and cared for the more than 800 false prophets, she had the evil tenacity to vow she would have Elijah murdered (1Kings 18 - 19). She also arranged the cold-blooded murder of a vineyard owner named Naboth in order to seize his land (1Kings 21).
Judah's Bloody Kings!
Ahaz ruled the Kingdom of Judah from 735 to 715 B.C. He not only indulged in such evil as offering sacrifices to pagan gods, he also burned incense to idols on many hilltops, under spreading trees and on many street corners of Jerusalem. He also burned HIS OWN CHILDREN as a perverse sacrifice to one of his pagan deities (2Kings 16:3 - 4, 2Chronicles 28:24). He is considered one of the the most evil and worst kings of Judah.
Manasseh reigned over the Kingdom of Judah longer than any other ruler did (696 to 642 B.C.). Although he was the son of righteous King Hezekiah, he led a life that indulged in many forms of evil. He rebuilt many of the pagan altars his father had rightly tore down (2Kings 21:3) and even resorted to building altars, dedicated to foreign gods, within the confines of Jerusalem's temple (verse 4)!
Manasseh encouraged the worship of celestial objects and practiced "black arts" such as using enchantments and contacting dead spirits. He even went so far into the depths of evil as to have one of his sons burned alive as a sacrifice to one of the gods he worshipped (verses 3, 6).
Menahem was king of Israel for ten years (752 to 742 B.C.). Known for being brutal, he murdered King Shallum in order to take the throne (2Kings 15:14). He could fly into an intense, evil rage when he did not get what he wanted.
One example of Menahem's evil, uncontrolled anger occurred when the city of Tiphsah refused to welcome him into the city. Enraged at their rejection, he conquered the city and killed whomever he could find. He even resorted to the gruesome act of ripping open women who were pregnant (2Kings 15:16).
New Testament Sinners
Herod the Great was known for his intense anger and willingness to do evil in order to achieve his goals. Fearful of losing his power and prestige, he attempted but failed to trick the Parthian Magi into revealing the exact location of baby Jesus so that he could kill him. Unable to narrow down where the young Savior was living, he took the drastic step of killing ALL the male children living in and around Bethlehem (Matthew 2).
Herod appointed people to be the temple's High Priest then later had them killed. He also raided King David's tomb several times for anything he could steal. He even resorted to the evil of having several family members killed and accusing his own sons of crimes before Caesar in Rome!
Herod Antipas was Rome's ruler over Galilee and Perea from about 4 B.C. to 39 A.D. He married his brother's wife Heriodias, an act considered by most people like John the Baptist as being incest (Mark 6:17 - 19). Herod soon puts John in prison. During his birthday celebration his lust gets the best of him and he has John not only beheaded but has his head brought to the party on a silver platter (Matthew 14).
After Jesus is arrested, Herod Antipas mocks him to his face and belittles his claim of being a king by placing a royal robe on him (Luke 23:5 - 12).
Others in the New Testament also indulged in great evil. Saul, before his conversion into the Apostle Paul, zealously hunted down and killed countless Christians (Acts 8:1, 3, Galatians 1:13 - 14) even to the point of traveling to foreign cities to do so (Acts 9:1 - 2).
Judas Iscariot was a petty thief who was greedy, deceitful and a good liar. In spite of being personally taught by Christ as one of his close disciples, he betrayed his teacher to religious leaders who ultimately had him crucified.
Simon Magus was a man with a large ego who deceived most people he encountered with his black magic. Seeing the Holy Spirit given to those who repented, Simon sought to purchase this power for his own evil intentions. He was forcefully rebuked by Peter (Acts 8).