The Long-haired Fiend

The Long-Haired Fiend, sometimes known as "The Ghoul" of the "Long-haired Demon", is the alias given to the spirit of a mysterious and violent man existing in the Further and acts as the third main antagonist throughout Insidious and a minor antagonist in the sequel.

Insidious
The Long-haired Fiend appears three times throughout Insidious. In his first appearance, he, along with other spirits were seen pacing outside Dalton's room. He was the only one who entered the room, and disappeared before Josh arrived.

The second time, when the Lipstick-Face Demon temporarily possesses Dalton's body, the Fiend is seen trying to sexually assault Renai. He disappears after Elise forces the Demon from Dalton's body.

The third time, he guards the door leading into the Demon's lair and attempts to overpower Josh and take his body. He nearly succeeds in doing so, but through Elise's encouragement, Josh defeats and forces him back into the darkness.

Insidious Chapter 2
The Long-haired Fiend made another appearance in the sequel as a minor antagonist. The spirit of an elderly man points Josh and Carl to the direction of the Lambert house, where Josh spots the Fiend in front of the house, smirking sinisterly before venturing inside. In the real world, Renai hears the baby crying and goes into the room to investigate. Renai sees the Fiend once again, looming behind a curtain and Renai screams for Josh.

Josh hurries into his home and finds the spirit on the verge of tormenting his family once again. He and the Fiend grapple, but Josh is no match for the supernatural prowess of the spirit and is brought into submission by the Fiend. As things look grim, the spirit of Elise manifests and catches the attention of the Fiend. Telling the malicious spirit to 'go to hell', she brandishes light from her lantern which stuns the Fiend and forces him out through the window, exorcising the Fiend from the Lambert residence once more.

Appearance
Unlike the other spirits inhabiting the Further, the Long-haired Fiend is actively malicious and has attacked the Lambert family on a few occassions.

His appearance and mannerisms suggests he may have been a criminal in his former life and descended into the Further when he died. As a ghost, his face seems to have degenerated, hence why he is labeled as 'the Long-haired Fiend'.

He wears a black leather trenchcoat, sports dark hair and eyes, and has gaunt, crackling skin.

His apperance constantly changes, from appearing as a ghoul, to a menacing "Long-Haired Fiend".

Trivia

 * Possibily, The Long-haired Fiend may had formed an alliance with the Lipstick-Face Demon, and Parker Crane in the first film.
 * Played by actor J LaRose in both films.
 * It is possible that he made a third apperance in the first film (although it would be his first apperance) when Renai wakes up after having a nightmare, the Long-haired Fiend is pacing outside the window, and then he somehow manages to enter the house and tries to sexually assualt Renai.