Spoiler Alert: Contains spoilers from the manga

1. Kuma

Kuma’s Actions In Saboady Were Recently Revealed To Be Supportive Of The Straw Hats

Before the heartbreaking demise of Ace during the Marineford arc, the Straw Hats were split up at the hands of Kuma during the Saboady arc. Not formidable enough at this pre-time skip phase of the story, Luffy found that he stood no chance against Kuma and neither did any of the rest of the crew.

While it is now known that Kuma split each of them up in an attempt to save them as they were not strong enough, Luffy unbeknown to this, broke down in tears and full-fledged frustration after a short one-sided battle between the two. Just like Luffy, fans saw this as one of the most shocking and emotional fighting sequences of the series at the time.

2. Sanji

The Wholecake Island Arc Saw Sanji Forced Into Marriage

After Sanji was forced into marriage with Big Mom’s daughter at the hands of Vinsmoke Judge, his father, it resulted in an ugly confrontation between him and Luffy. In an attempt to release the Straw Hats from the burden of trying to save him, while deeply wanting to save his own family despite their hatred toward him, Sanji beats Luffy in front of his brothers.

This was yet another emotional battle, not only in the sense of Sanji attacking his captain but simply due to Luffy’s reluctance to fight back and Sanji’s disgust at what he feels he has to do. It leads to a memorable moment that showcases Luffy pleading to Sanji, that he cannot become the King of the Pirates without him.

3. Rob Lucci

Robin’s Life And The Rest Of The Straw Hats Were At Risk

The bout between Monkey D. Luffy and Rob Lucci during the Enies Lobby arc is arguably the best battle in the entirety of One Piece. While plenty of this certainly comes down to the intense and engaging exchanges between them throughout a plethora of episodes, it is also due to the emotional weight of the entire sequence. This was Luffy’s first real tough opponent besides Crocodile, as the pair at the time were viewed as being at the same level strength-wise.

With Robin’s memorable cry for help and her declaration of her wanting to live and travel with the Straw Hats, Luffy’s victory over Rob Lucci was the only thing standing in the way of this toward the end of the arc. Lucci’s defeat was not only an exceptional spectacle for fans, but it was also the culmination of Robin’s journey to becoming free off the back of the heartbreaking Ohara flashback.

4. Jinbei

Ace’s Death Almost Killed Luffy

While this was less of a battle compared to Luffy’s other bouts, his anger and frustration towards Jinbei after learning of Ace’s death was enough to tug on the heartstrings of fans. Luffy takes his heartbreak out on Jinbei and attacks him, but is bested when Jinbei calms him down, allowing him to realize that although Ace is gone, he still has his friends.

The emotions here are linked to fans’ learning of Luffy, Ace, and Sabo’s past, and also the feelings shared between Luffy and Garp following the catastrophic events of Marineford, which mainly stemmed from Akainu’s savage actions.

5. Garp

Garp Was Conflicted Between Family And Duty During Marineford

Out of all of Luffy’s intense and emotional encounters with other characters in the series, his short clash with his grandfather, Garp, is the most emotional. Looking back on the events of Marineford now during the final saga of the series, and acknowledging Ace’s death, Garp’s planned fall from Luffy’s Gear Second blow holds so much emotional weight.

In an internal tug-of-war of family or duty, Garp ultimately decides to allow Luffy to hit him, resulting in Luffy successfully saving Ace from his execution. This is doubled down by Garp’s discussion with Ace, and his heartbreak at Luffy and Ace not becoming Marines, which would prevent him from his troubled state. When Ace dies at the hands of Akainu, it hits so much harder for both Luffy and Garp, knowing that Garp gave up his duty hoping that Ace would get out alive, but ultimately failed and lost his beloved surrogate child.