Belial
Belial (Hebrew: בְּלִיַּעַל‎, Bəlīyyaʿal) is a term occurring in the Hebrew Bible/Old Testament which later became personified as the devil in Christian texts of the New Testament. Alternate spellings include Baalial, Balial, Belhor, Beliall, Beliar, Berial, Bylyl and Beliya'al. In the Secret Book of John, an early Gnostic text, the ruler of the underworld is referred to as Belias.

Hebrew Bible/Old Testament
Belial is a Hebrew word "used to characterize the wicked or worthless". The etymology of the word is often understood as "lacking worth", from two common words: beli- (בְּלִי "without-") and ya'al (יָעַל "to be of value").
Some scholars translate it from Hebrew as "worthless" (Beli yo'il), while others translate it as "yokeless" (Beli ol), "may he have no rising" or "never to rise" (Beli ya'al). Only a few etymologists have believed it to be an invented name from the start.The word occurs twenty-seven times in the Masoretic Text, in verses such as the Book of Proverbs (Proverbs 6:12), where the King James Version (KJV) translates the Hebrew phrase adam beli-yaal as "a naughty person".In the Hebrew text, the phrase is either "sons of Belial" or simply "sons of worthlessness". Phrases beginning with "sons of" are a common Semitic idiom, such as "sons of destruction" or "sons of lawlessness".Of these 27 occurrences, the idiom "sons of Belial" (בְּנֵֽי־בְלִיַּעַל beni beliyaal) appears 15 times to indicate worthless people, including idolaters (Deuteronomy 13:13), the men of Gibeah (Judges 19:22, 20:13), the sons of Eli (1 Samuel 2:12), Nabal, and Shimei. The Geneva Bible (1560) uses "wicked", and at the Book of Judges 19:22 has the marginal note "Ebr [Hebrew] men of Belial: that is, given to all wickednes." In the KJV these occurrences are rendered with "Belial" capitalised:

"the sons of Eli were sons of Belial" (KJV)In modern versions these are usually read as a phrase:

"the sons of Eli were worthless men" (1 Samuel 2:12, NRSV and NIV)
"the wicked men of the city" (Judges 19:22, NIV)"Belial" is applied to ideas, words, and counsel, to calamitous circumstances, and most frequently, to worthless men of the lowest sort, such as men who would induce worship of other gods; those of Benjamin who committed the sex crime at Gibeah; the wicked sons of Eli; insolent Nabal; opposers of God's anointed, David; Rehoboam's unsteady associates; Jezebel's conspirators against Naboth; and men in general who stir up contention. Indicating that the enemy power would no longer interfere with the carrying out of true worship by his people in their land, YHWH declared through his prophet: "No more will any worthless person pass again through you. In his entirety he will certainly be cut off."

Second Temple period
The term belial appears frequently in Jewish texts of the Second Temple period (texts classified by Christians as the Old Testament pseudepigrapha and apocrypha). Also a large number of references to Belial are evidenced in the Dead Sea Scrolls discovered at Qumran from 1948.

Dead Sea Scrolls
In The War of the Sons of Light Against the Sons of Darkness, one of the Dead Sea scrolls, Belial is the leader of the Sons of Darkness:

You made Belial for the pit, angel of enmity; in darkness is his domain, his counsel is to bring about wickedness and guilt. All the spirits of his lot are angels of destruction, they walk in the laws of darkness; towards it goes their only desire.
In the Rules of the Community, God is depicted as saying, "I shall not comfort the oppressed until their path is perfect. I shall not retain Belial within my heart." Belial controls scores of demons, which are specifically allotted to him by God for the purpose of performing evil. Belial, despite his malevolent disposition, is considered an angel.Belial's presence is found throughout the War Scrolls and is established as the force occupying the opposite end of the spectrum of God. In Col. I, verse 1, the first line of the document, it is stated that "the first attack of the Sons of Light shall be undertaken against the forces of the Sons of Darkness, the army of Belial." This dichotomy sheds light on the negative connotations that Belial held at the time.
The War Scroll and the Thanksgiving hymns both delve into the idea that Belial is accursed by God and his people, and shows how the existence of Belial in this world can be attributed to the mysteries of God since we can not know why he permits the dealings of Belial to persist.
In the Dead Sea Scrolls, Belial is further contrasted with God. These are the Angel of Light and the Angel of Darkness. The Manual of Discipline identifies the Angel of Light as God himself. The Angel of Darkness is identified in the same scroll as Belial.Also in The Dead Sea Scrolls is a recounting of a dream of Amram, the father of Moses, who finds two watchers contesting over him. One is Belial who is described as the King of Evil and Prince of Darkness. Belial is also mentioned in the Fragments of a Zadokite Work (which is also known as The Damascus Document (CD)), which states that during the eschatological age, "Belial shall be let loose against Israel, as God spoke through Isaiah the prophet." The Fragments also speak of "three nets of Belial" which are said to be fornication, wealth, and pollution of the sanctuary. In this work, Belial is sometimes presented as an agent of divine punishment and sometimes as a rebel, as Mastema is. It was Belial who inspired the Egyptian sorcerers, Jochaneh and his brother, to oppose Moses and Aaron. The Fragments also say that anyone who is ruled by the spirits of Belial and speaks of rebellion should be condemned as a necromancer and a wizard.

Jubilees
In the Book of Jubilees, uncircumcised Israelites are called "sons of Belial".

Testament of the Twelve Patriarchs
Belial is also mentioned in the Testaments of the Twelve Patriarchs. The author of the work seems to be a dualist because he presents Belial as God's opponent, not as a servant, but does not mention how or why this came to be. Simeon 5:3 says that fornication separates man from God and brings him near to Belial. Levi tells his children to choose between the Law of God and the works of Belial It also states that when the soul is constantly disturbed, the Lord departs from it and Belial rules over it. Naphtali contrasts the Law and will of God with the purposes of Belial. Also, in 20:2, Joseph prophesies that when Israel leaves Egypt, they will be with God in light while Belial will remain in darkness with the Egyptians. Finally, the Testament describes that when the Messiah comes, the angels will punish the spirits of deceit and Belial and that the Messiah will bind Belial and give to his children the power to trample the evil spirits. For many hath fornication destroyed; because, though a man be old or noble, it maketh him a reproach and a laughing-stock with Beliar and the sons of men.

Ascension of Isaiah
In the Ascension of Isaiah, Belial is the angel of lawlessness and "the ruler of this world", and identified as Samael and Satan.
And Manasseh turned aside his heart to serve Belial; for the angel of lawlessness, who is the ruler of this world, is Belial, whose name is Matanbuchus.

Christianity/New Testament
The word occurs just once in the New Testament, when Paul the Apostle asks:

[W]hat concord hath Christ with Belial? or what part hath he that believeth with an infidel?
The spelling found in most manuscripts of 2 Corinthians is actually Beliar (Βελιάρ) not Belial (Βελίαλ). This is the reading preferred by textual scholars and the change of -l to -r is attributed to a common change in Aramaic pronunciation.The Jewish Greek Septuagint, later the Old Testament of the early Christian church, generally renders the "sons of Belial" verses in the Hebrew Bible either as "lawless men", by idioms "sons of the pestilence", rather than a personal name "sons of Belial":

andres paranomoi ("lawless men" ἄνδρες παράνομοι) (Deuteronomy 13:13)
huioi loimoi ("sons of the plague" υἱοὶ λοιμοὶ) (1 Samuel 2:12)The Septuagint also avoids Belial in the singular so Shimei (2 Samuel 16:7) when he cursed David, "Come out, come out, thou bloody man, and thou man of Belial" is rendered "you lawless man" (paranomos), and Hannah to Eli "Count not thine handmaid for a daughter of Belial" is rendered "don't count your maidservant as a daughter of the pest." The Latin Vulgate and Syriac Peshitta Old Testaments in some cases follow the Greek, in other literalize as Hebrew. The single New Testament use is preserved "Belial" in Latin and Syriac.

Resurrection of Jesus Christ (by Bartholomew)
In the Resurrection of Jesus Christ (by Bartholomew) of the New Testament apocrypha, Belial was visible along with 666 fallen angels when Michael was commanded by Jesus to show Hell to his disciples.

Rabbinical literature
The Talmud and rabbinical interpretation generally follow a non-supernatural view, an allegorical personification of evil, as with rabbinical interpretations of evil. The phrase "sons of Belial" from the Torah continued to retain currency.In the Teliya Yeshu, the name Belial is given to Yeshu, the son of Miriam Magdala, also called Ben Stada and Ben Pantheras in the Wagenseil version of the same as well as in the Talmud.

English literature
John Milton, Paradise Lost, Book I:

John Milton, Paradise Lost, Book 2:

Robert Browning (1839), "Soliloquy of the Spanish Cloister", eighth stanza:

Occult
The 17th-century grimoire The Lesser Key of Solomon mentions Belial, as does Aleister Crowley's Goetia (1904) and Anton LaVey's The Satanic Bible (1969). In The Satanic Bible (The Book of Belial), Belial means "without a master", and symbolizes independence, self-sufficiency, and personal accomplishment.
In 1937, Edgar Cayce used the term "sons of belial" and "sons of the law of one" for the first time in one of his deep trance readings given between 1923 and 1945. Cayce was often referred to as the "sleeping prophet" who gave over 2,500 readings to individuals while in a deep trance state.  While his definition of the sons of belial was consistent with the Hebrew meaning of "worthless" individuals focused on self-gratification, Cayce went on to use the term frequently to compare opposing human forces at work in pre-historical times related to the early development of Atlantis.

In popular culture
Popular culture in the 20th century included many references to Belial; notably in the celebrated silent film Nosferatu (1922), Aldous Huxley's novel Ape and Essence (1948), Philip K. Dick's novel The Divine Invasion (1981), the cult horror film Basket Case (1982), Dean Koontz's novel Phantoms (1983), and Graham Masterton's novel Master of Lies (1991). Belial has also experienced a resurgence in popularity during the 21st Century in numerous media, with video games being the most prominent.

Digimon Adventure 2 BelialVamdemon.
In the Gothic (series) game series Beliar is the god of death.
In the Square Enix game "Final Fantasy Tactics: War of the Lions" a character named Wiegraf uses the power of a mystical stone and is then possessed by the demon "Belial".
In the 2005 horror film, The Exorcism of Emily Rose, Belial is featured as the Devil's representative who possesses the title character.
In the real time strategy game Dungeon Keeper's Deeper Dungeons expansion the final level is titled "Belial".
In the role playing game Vampire: the Requiem, Belial's Brood is a covenant of vampires that serve Vice and evil forces, consorting with infernal spirits for power.
Blizzard Entertainment's video game Diablo 3 has Belial function as the final boss of Act 2 in its storyline. In the City of Caldeum, where Belial takes residence, there are definite Arabic tones for the art direction and setting in the aforementioned chapter. Also known as the "Lord of Lies" and the "Master of Deception", Belial is regarded as one of the four Lesser Evils and seven Great Evils in the mortal realm that seek to make this world an outpost of Hell itself.
Westwood Studios's PC game Lands of Lore: Guardians of Destiny features Belial as its main antagonist, portraying him as an evil god with a devil-like appearance.
In the Warhammer 40k universe Belial is the current Grand Master of the Deathwing of the Dark Angels Space Marine Chapter which has other characters named after bleaker Abrahamic entities, such as Samael, the poison of God, and Azrael, the Angel of Death.
In the mobile game Puzzle and Dragons, Belial is a monster that is part of the Archdemon series.
In the book The Little Ships by J.A. Sutherland, the main character sails in a spaceship named Belial.
"Belial's Meat" is a health item in the video game Off by Mortis Ghost.
In the video game Binding of Isaac, the Book of Belial is an activated item that increases damage for the current room.
In the mobile game Crash Fever, Belial is one of the first protagonists.
In Granblue Fantasy, Belial is a "fallen angel", appearing in the What Makes The Sky Blue 2 and 3 event(s) as one of the main antagonists.
"Belial" is the theme held in meditation by Vaughn Benjamin (Akae Beka) on the Midnite & Ras L Collaborative album Thru & True (2006).
Belial is referenced, among other demons, on Mayhem's 2014 studio album Esoteric Warfare. Belial is mentioned in "Pandaemon," the fourth track on the LP.
Lord Belial is a Swedish black metal band.
In the Ultra Series, Belial is the namesake of recurring villain Ultraman Belial, a rogue Ultraman that made a dark pact to gain the ability to control and merge with monsters, with his alternate forms occasionally taking on demonic appearances.
Belial is mentioned in the track "Fall from Grace" from Morbid Angel's 1991 album, Blessed Are the Sick.
In Cassandra Clare's bestselling Shadowhunter Chronicles, Belial is one of the Prince of Hell as well as the demonic father of a major character, Theresa Gray, who was the protagonist of The Infernal Devices. In Shadowhunters, the television adaptation of the novel series, Belial is the demonic father of a supporting character in season 3, the warlock Lorenzo Rey. Belial is mentioned as Lorenzo's father in the episode "City of Glass".
In the 2019 comedy horror film, Ready or Not, the name of the demonic presence, Mr. Le Bail, is an anagram for Belial.
In the Shin Megami Tensei and Persona games, Belial appears as a demon and persona to be used in combat
In the 2021 Anime series Beyblade Burst Dynamite Battle the main character Bell Daikokuten named his Beyblade Dynamite Belial. Later on, he upgrades Dynamite Belial into Dangerous Belial after its destruction. The name of the bey, however, was changed to Belfyre in the dub and in Hasbro toy releases.
In Season 2 episode 5 of  The Chosen, Caleb is possessed by Belial and shares who he is while conversing with Mary.

See also
List of theological demons
Asmodai
Bel
Demon
Devil
Samael
Satan
Serpent
Sin

References
S. L. MacGregor Mathers, A. Crowley, The Goetia: The Lesser Key of Solomon the King (1904). 1995 reprint: ISBN 0-87728-847-X.
Metzger, Bruce M.; Coogan, Michael D., eds. (1993). The Oxford Companion to the Bible. Oxford, UK: Oxford University Press. ISBN 0-19-504645-5.

External links
Belial entry at Jewish Encyclopedia.com
Catholic Encyclopedia entry on Belial
Occultopedia entry on Belial
Belial article from the Mystica