10- Nico Robin
Luffy and Nico Robin initially start out as enemies, but after Robin saves his life in Alabasta, Luffy grows to trust her more deeply which he shows by letting Robin join his crew without any hesitation.
9- Trafalgar Dr. Water law
Trafalgar Law and his crew brave the Battle of Marineford and the attacks of the Navy Admirals only to save Luffy.
8 – Marco Fenix
After Ace’s death, he stopped Akino from killing Luffy and urged the other Whitebeard Pirates to save Luffy, with Ace sacrificing his life for him.
7 – Emporio Ivankov / Vinsmoke Reiju
Help Ivankov save Luffy’s life with his healing hormones. He escorts Luffy to Level 5.5, his “Newkama Land”, and chains Luffy to a platform as he explains his treatment: by taking ten years off Luffy’s life, he will give him a small chance of surviving the poison. He then injected healing hormones into Luffy, and Luffy’s pain and anguish consumed him. Inazuma predicted that it would last for two and a half days. However, Luffy manages to successfully complete the operation in 20 hours.
During their first meeting, Reiju immediately noticed that Luffy was slowly dying from the effects of devouring the poisonous Armored Stonefish skin. Unlike her younger brother Yoongi, Reiju chooses to spare Luffy’s life, absorbing the poison from his body as thanks to her for everything the Straw Hats have done for Sanji.
6 – Roronoa Zoro
In Thriller Bark, Zoro decided to give up his life to save Luffy from Bartholomew Kuma because he was willing to die for his captain’s dream. Kuma found this confidence impressive as he was touched by Zoro’s sympathy.