The Lost (The Binding of Isaac)

The Lost is the Bigger Bad of the Binding of Isaac and a ghost version of Isaac, presumably a ghost version of Isaac that has died in one of the levels of the basement.

Biography
At the beginning of the game a cutscene is shown depicting Isaac's Mom and Isaac enjoying life until she one day hears a voice from above. The voice tells her that Isaac has been corrupted by sin and needs to be saved. Isaac's Mother does as the voice says throughout the cutscene, believing that it is God. She took away all of Isaac's toys and clothes, locked him in his room, and finally attempted to murder him with a knife she obtained from the kitchen. Isaac panicked and tried to find a way out of the room and finally finds a trap door to the house's basement, he jumps down just as his mother makes it to Isaac's room and falls into the unknown depths below.

In a level transition, which usually depicts Isaac's memories from his life before he fell into the basement, it is shown that the voice from above that told Isaac's Mom to do all of those things to him was in fact the Lost.

Appearence


Being Isaac as a ghost, the Lost has a similar face as him. Two round black eyes, typically with tears streaming down from them. His head is circular and he's almost always seen frowning. His body is that of a typical ghost, not having any legs and ending in a wispy tail. Although not shown in Isaac's drawings, while in game is body swishes around and wisps of him fly off even when not walking.

With a rather large head and his body ending in a tail, when completely still and in Isaac's drawings he somewhat resembles a sperm cell. The Lost is also shown to have arms when picking up items, using cards or taking pills. His arms are not visible when they aren't in use.

Personality
Not much is known about the actual personality of the Lost, but he is shown to be very sorrowful and pitiful in much of the official art of himself.

There is no confirmed reason as to why he committed such an evil act, upon a version of himself and his own Mother no less, especially when he is depicted as such a tragic and weak soul.

Trivia
- Originally in the Binding of Isaac Rebirth the Lost could be unlocked as a playable character in a very convoluted way. These must be done in order and dying in any other way will require the player to start over: - The method of unlocking the Lost has later been changed in the Binding of Isaac: Afterbirth DLC to Isaac dying on sacrificial spikes while holding a Missing Poster trinket. - The Lost's health is shown as "?" on the character selection screen, this is because the Lost has no health and dies in one hit (if not carrying an item that could absorb hits such as the Holy Mantle or Infamy) - The Lost can take devil deals for free. - In earlier versions of the game the Lost would die if the run was exited and then continued. - During victory laps, the player character will turn into the Lost by the third lap. He will not start off with any of his starting items such as the Holy Mantle, but will still retain items gained from the last lap. - In the original the Binding of Isaac, when Isaac dies the Lost isn't shown flying up. Instead a light shines on Isaac and he explodes into blood.
 * Die as Isaac to a Mulliboom in the Basement or Cellar
 * Die as Magdalene to her own bomb in the Caves or Catacombs
 * Die as Judas to a Mom attack in the Depths or Necropolis (must be an attack by Mom and not by an enemy spawned by her)
 * Die as Azazel to Satan in the Sheol (must be a Satan attack and not the Fallen or an enemy spawned by Satan)