Captain James Bartholomew Hook is a nefarious pirate originating from the London world connected to Neverland, allied to the Friends on the Other Side as one of the Dark Masters.
Neverland is a near paradise, ruled by the (usually benign) Peter Pan. Naturally, the Friends would hate for a place like this to even exist, and they'd really hate Peter Pan. Fortunately, Neverland has so much good magic that none of their magic can even approach it. So they found someone with enough hatred toward Pan – Captain Hook. They offer him immortality (which explains why he didn't age at all in the sequel and how he survives some Amusing Injuries) and send him on his way. Sure, he's incompetent, but what else can they do? (Except possibly be responsible for Tick Tock the Crocodile's disappearance in the sequel.)
- But Maleficent does have high hopes for Captain Hook and has granted him a position of general of the seas on the Friends side. He's also a Dark Master agent, just to add to that.