The Crooked Man is the monster who frequently tries to kill David during the course of the game.
His real name is Duke MacGahan (デゥーク・マクガーン Dukku Makugaan) and he is the tenant David's been looking for in the whole game. He committed suicide years ago and he is the true identity of the Crooked Man.
If his facets and the notes he wrote during the course of the game are to be believed, Duke was an idealist young man, who due to his troubled past (being abandoned by his mother, failing to become a lawyer and being dumped by his girlfriend) became depressed and eventually committed suicide.
After becoming a vengeful spirit (the Crooked Man), he becomes resentful and upon seeing David, he immediately dislikes him. He discovers David moved into the flat he lived in. He came to hate David for being so much like himself, but staying happy. He tries to drive him to suicide, or kill him personally. Part of him wanted to save David from going down the same path as Duke and killing himself.
As the Crooked Man, he generally goes after David, but if Sissi, D or Fluffy are around he prefers going after them and trying to kill them much to David's confusion. After it is revealed that the three of them are facets of Duke, it makes perfect sense. Sissi has regrets over lost love, D has regrets over failed dreams, and Fluffy's been abandoned. These are all the aspects of Duke (and David, as they were both so similar) that ultimately led to his eventual suicide. They were probably created by the Crooked Man as a means of stopping David from killing himself.
- The Crooked Man represents Duke's resentment and despair. However, during Stage 3 there is a note from an otherwise-unrelated man who killed himself in order to get away from...something. David also says that he's been hearing "voices" in his head, long before the Crooked Man started coming for him. The Crooked Man in the game is Duke's, but apparently David's had one of his own for some time and it's part of the reason Duke decided to step in. It's even possible that the creature who tries to make David shoot himself in Stage 4 was David's own Crooked Man, not Duke's.
- The Crooked Man's immensely bent neck was a result of his neck snapping after he hanged himself.
- It is stated in Uri's official twitter account that Duke's eyes are green. If you look closely on the scene where David shoots himself, his eyes become green.
- It was also stated in Uri's website/blog that Duke supposedly used Camel cigarettes, despite the fact that David gave him a pack of Marlboro.
- If you look closely on the Treasure Hunt puzzle on Hotel Ruhenheim, the kid who drew it looks similar to a young Duke MacGahan due to his black hair.