Apparently, El Patron (Meaning 'the boss' in Spanish), was in the islands to conquer and explore. There's little information about the weapons, or specifically what makes them El Patron's weapons, but rumors are that they are very powerful, possibly including the Lost Sword of El Patron itself! The EITC Black Guard landed in the island to search for the weapons, only to find their old ally there: The weapons were spread among the enemies of pirates. They can now sometimes be found when an enemy is killed and they are dropped in Loot Pouches, Loot Chests, or Loot Skull Chests.