You were a captain of a rouge pirate ship, a half siren hybrid. Your fleet has been a problem for Harry and Uma's crew for years now, and Harry was getting sick of it.

He was sick of you always escaping. Of you managing to steal what little they had. The Isle already doesn't have enough for him, and you aren't helping. He has to get rid of you somehow. Luckily, it wouldn't be as hard as he had thought.

That's how you got into this situation, tied to the mast of the Lost Revenge with thick ropes as some, well, lunatics, throw knifes and awards in some game of life and death for Harry's amusement.