The Temple Ruins Version 2.3.1

Ball & Chain Trooper
- Location: Hyrule Castle
  Effective Weapons: Boomerang, Sword
  
  Attacks: As the name implies, the Trooper carries a large Ball & Chain. He will periodically swing it around a few times. The first couple swings will be short range, but the last swing will extend and reach when you are farther away.
  
  Novice Strategy: The dungeon contains two cells. One cell is locked and Princess Zelda is inside. The other cell is not locked and contains three pots. Pick up one of he pots and carry it until the Ball & Chain Trooper is within throwing distance. Then, throw the pot at him. Hit him with two of the three available pots to defeat the Trooper and receive the Big Key
  
  Veteran Strategy: Equip the boomerang and get the Trooper within the throwing distance. You can stun the Trooper briefly using the boomerang and then hit him a few times with your sword before he strikes back. Time your boomerang throws and sword hits carefully and you can avoid all damage. It will take several hits to defeat him.
  
  Other Tips:
  - The pots inside the unlocked prison cell contain hearts.
  - The Ball and Chain Trooper really isn’t a boss at all. Later in the game, when you return to Hyrule Castle, you will face many of them as regular enemies. However, they will be easier to defeat because you will be better equipped to deal with them.