Trigon

Trigon is an interdimensional demonic being dedicated to dominating the entire universe. He is worshipped by a cult of countless acolytes. He is the father of Rachel Roth/The Raven, whom he concieved with Angela Azarath.

Banishment
Not much is known about Trigon's origin, however, whatever is known of his life has been recorded in an ancient text known as the "Gul'ron Dez Dire" ("Death of Worlds"). The age of the book implies that Trigon has been around for many years. Long ago, he arrived in the human dimension and managed to destroy a world. As a result, he was somehow forbidden to return, imprisoned in his realm for all eternity.

Prophecy
Trigon was somehow summoned back to Earth in order to conceive a child with one of his acolytes, Angela Azarath, with the intention of having that child, Rachel, serve as his doorway into the human dimension. Due to his banishment, he was forcibly taken back to his world. The child would also be the anchor that keeps Trigon in their dimension. Once he returns, he will engulf worlds, such as Tamaran, in darkness and they will burn. Earth will be one of his first targets. Other organizations, such as Doctor Adamson's had knowledge of his return.

Return
Interfering with his plans, a woman named Melissa Roth took Rachel as an infant and ran away. They hid at Saint Paul's Convent for some time in hopes of finding sanctuary and escaping Trigon and his followers. Over time, Melissa would raise Rachel as her own and keep her background a secret from her. For over thirteen years, Trigon's acolytes searched for Rachel. At some point, one of his acolytes managed to locate them and killed Melissa, but Rachel escaped as they continued to pursue her nonstop.

One night, while Gar was in a life-threatening condition, Angela managed to pressure Rachel into summoning her father from his realm, stating that he was far more powerful. Contacted through a mirror in the house, a hand was reached through to him and he was pulled out of his dimension, being able to freely roam Rachel and Angela's world. As promised, he healed Gar, but with the intention to wreck havoc.

Powers

 * Demonic physiology: As an inter-dimensional demon, Trigon has a host of unique abilities. Although he often appears in human form, his real appearence is huge and mostrous-like, with multiple eyes, horns, hooves and red skin. Trigon's presence disrupts energy generation and causes blackouts.
 * Dimensional travel: Trigon can teleport to and from his demonic dimension, although he need his daughter as a doorway in order to do it after he was banished.
 * Illusion casting: Trigon can create elaborate illusions to fool others, being even capable to appear like an ordinary human, or creating fake realities.
 * Biokinesis (possibily): Just like his daughter, Trigon was able to act on other beings bodies and organs by healing them or reversing the process, however, he is said to be far more powerful than Rachel.
 * Healing: Trigon is able to resurrect others being or heal wounds in mere seconds just by imposing his hands.
 * Telepathy: Trigon is able to gaze into the minds of mortals. He can learn a person's entire history by reading their mind, and usually reads his opponents' minds to learn how he can manipulate them.
 * Mind Control: Trigon can possess anyone he feels necessary for his plots. He is capable to enslave and control anyone if he surrenders to his inner darkness.
 * Force field generation: Through concentration, Trigon is able to project fields of psionic force which he can manipulate in shape and size, even giving them cloaking capabilities.
 * Immortality: As a demon, Trigon does not age like mortals and is said to have existed for centuries, if not millennia or even the dawn of time.

Abilities

 * Master manipulator: Trigon is a master of deception and manipulation, he often pose in order to appear as benign and is perfectly able to trick people into doing wht he want in order to make them surrender to their inner darkness.
 * Expert Leader: Trigon is said to be very charismatic and has countless of acolytes who followed him blindly.

Season 1

 * "Origins" (mentioned)
 * "Together" (mentioned)
 * "Asylum" (mentioned)
 * "Donna Troy" (mentioned)
 * "Koriand'r"
 * "Dick Grayson"

Behind the scenes

 * In the DC comics, Trigon is a demon lord existing in an alternate dimension, and the father of Raven, known on Earth as "Rachel Roth".