- Episode 5x16, The Incident
While the statue was still whole, and the Black Rock was coming to the island, Jacob sat on the beach and another man, Jacob's "friend" came to talk to him. Jacob asks if he's there because of the ship and the man says he is and wonders how the ship found the island, then says that he know Jacob brought them there to prove him wrong. He says they come, they fight, they destroy, and they corrupt.
The man asks if Jacob has any idea how badly he wants to kill Jacob and Jacob says yes. The man says, "One of these days, sooner or later, I'm going to find a loophole, my friend." Jacob says when he does, he'll be right there.
Many, many years later, the "friend" impersonates John Locke. He and Ben go into the four-toed statue to talk to Jacob. When they see him, Man in Locke says, "Hello, Jacob," and Jacob says, "You found your loophole."
On Man in Locke's instructions, and despite the fact that Jacob tells Ben he has a choice, Ben kills Jacob.
- Episode 6x9, Ab Aeterno
In 1867, Man in Black turns into the smoke monster and kills the officers of the Black Rock. He later returns to Richard as Isabella and tells him that she's seen the devil and they have to get out of there. She is then killed.
Man in Black goes into the Black Rock and tells Richard that he's in Hell. He has the keys to the chains and tells Richard that if Richard will help him, Man in Black will help Richard. Richard agrees.
Man in Black frees Richard and then tells him he'll have to kill the devil. He tells Richard to go to the statue and to stab the devil before he has a chance to speak.
Richard returns and Man in Black says that if he goes with Jacob, he will never see his wife again. Richard says he has a gift from Jacob and gives Man in Black a white rock. Man in Black gives Richard Isabella's necklace, saying he found it on the ship.
Jacob goes to Man in Black. He says that Man in Black tried to kill him and Jacob says that Man in Black will never leave the island as long as Jacob is alive. Man in Black says he'll kill Jacob and Jacob says that someone will replace him. Man in Black says he'll kill the replacement too. Jacob gives Man in Black the wine and then leaves. Man in Black breaks the wine bottle against a rock.
- Episode 6x15, Across the Sea
Mother helps Claudia deliver Jacob and then his brother and then she wraps him in a dark blanket, places him next to Jacob in his light blanket, and then beats their mother to death with rock.
As a teenager, the boy in black finds a game in the sand. It consists of a playing board and white and black stones. Jacob comes over and asks what it is. Teenager in Black says it's a game and you play it. Jacob asks how he knows how and Teenager in Black says he just knows. Jacob wants to know how to play and Teenager in Black says he'll show him only if he promises not tell Mother, because she'll take it away. Jacob promises.
Later, Mother comes to Teenager in Black as he sits on the beach. He knows that Jacob told her about the game and she says that Jacob cannot tell a lie. Teenager in Black thinks the game came from across the sea and is disappointed when Mother says it came from her and there is nothing across the sea. She tells him that he is special.
Later, Teenager in Black and Jacob get spears and chase after a boar. They see other men and are shocked. They run back to tell Mother and she seems worried. She says that she and her boys are there for a reason, but it's not time yet.
She blindfolds them and leads them out into the jungle. They ask if she knew about the people and she says yes. She hadn't told them because they are dangerous and she didn't want to frighten the boys. They ask what makes them so dangerous and she says, "The same thing that makes all men dangerous. They come, they fight, they destroy, they corrupt. It always ends the same."
She tells the boys that the people are from the other side of the island and to stay away from them or they will hurt the boys because they are people and that's what people do. Teenager in Black wants to know if that means they can hurt each other. Mother stops and takes off their blindfolds and says that she has made sure they can never hurt each other.
She turns them around and they see a cave with amazing light coming from it. She says that is the reason they are there, because of the light. Every man has a little bit of the light in them, but they always want more, so she's protected this place, but she can't protect it forever and one of them will have to take over.
Later, Jacob and Teenager in Black play the game, but Jacob makes a move that Teenager in Black says he can't do. Jacob asks why and Teenager in Black says, "I found it. One day, you'll find your own game and everyone else will have to follow your rules."
Over Jacob's shoulder, he sees Claudia. He stares at her and Jacob turns, but doesn't see anything. Teenager in Black says he's taking a walk and goes to find her. She tells him that Jacob can't see her because she's dead, and she has something to show Teenager in Black.
He follows her to the other side of the island where there is a little village of people. She says they came thirteen years ago, the day before Teenager in Black's birth, on a ship. He asks what a ship is and she says it's how they came across the sea. He says there is nothing across the sea and Claudia says that is where he came from and she is his mother.
While Mother and Jacob sleep, Teenager in Black gathers his and Jacob's stuff and then wakes Jacob and they sneak out. He tells Jacob to follow him to the people and they argue. Teenager in Black says their mother lied and Jacob tackles him and hits him. Mother breaks them up and Jacob says that Teenager in Black is leaving. Mother tells him that no matter what anyone tells him, he will never be able to leave the island. Teenager in Black wants Jacob to go with him, but Jacob decides to stay with Mother.
As an adult, Jacob goes across the island and watches his brother's people, then plays the game with his brother. Man in Black asks if Mother knows that Jacob visits him and Jacob says she never asks about him.
Man in Black is down in the magnetic hole and Mother appears. He shows her that he found the light and tells her that his people came up with a system and he's getting off the island. She hugs him and apologizes, and then slams his head against the stone.
When Man in Black wakes, he's on the ground above the hole and the hole is filled in. He sees smoke and goes to his village, which is burning. Everyone is dead. He fishes his game out of the fire and cries.
At her dwelling, Man in Black stabs his mother from behind. She falls to the ground and he asks why she wouldn't let him leave the island. She says, "Because I love you. Thank you." She dies and he cries over her. Jacob comes in and Man in Black tries to explain, but Jacob beats him and then drags him to the light. He throws him down in the creek and Man in Black hits his head and then floats face down into the light, where he disappears.
Man in Black Portrayed by: Titus Welliver