Answer:
"His determination was as unbreakable as Luffy's will to become the Pirate King."
Step-by-step explanation:
This allusion references the popular anime and manga series, One Piece, which follows the adventures of a young pirate named Monkey D. Luffy, who has an unwavering determination to become the Pirate King and find the One Piece treasure.
The allusion suggests that the person being described has a level of determination and perseverance that is similar to Luffy's. Just as Luffy is willing to face any obstacle in his quest to become the Pirate King, the person being referred to in this allusion is similarly dedicated and unyielding in their pursuit of their own goals.