While One Piece, Naruto, and Bleach are together considered the Big 3 anime from the Weekly Shonen Jump magazine, one of them is very much unlike the other two. As fans will know, all three series have great stories, characters, and lore behind them. However, when it comes to the protagonist, One Piece is quite different from its counterparts.
One may think that the difference between the protagonists is their personalities, but that is not the case here. While it is true that Monkey D. Luffy is quite different in personality compared to Naruto and Ichigo, there is a bigger reason that sets him apart, and it has to do with their parents' legacy.
Disclaimer: This article reflects the writer's opinion and may contain spoilers from several manga.
One Piece's Monkey D. Luffy is different from Naruto and Ichigo due to their legacies
In both Masashi Kishimoto's Naruto and Tite Kubo's Bleach, the series' protagonists Naruto Uzumaki and Ichigo Kurosaki are linked to their parents' legacies as they try to live up to them.
In the case of Naruto, he inherits something from both his parents, Minato Namikaze and Kushina Uzumaki. From Minato, Naruto essentially inherited his role as the Hokage of the Hidden Leaf Village and from Kushina, he inherited the huge chakra reserve trait of the Uzumaki clan.
Similarly, in the case of Ichigo, he inherited something from both his parents as well. Given that his father was once a Shinigami, he inherited his father's traits as one. Additionally, he also inherited the Quincy and Hollow traits from his mother. All in all, due to his parents, Ichigo Kurosaki was a Human, Shinigami, Quincy, and a Hollow.
With this, it is very clear that both Naruto and Ichigo essentially inherited their strength from their parents. This also accounts for their legacy, as both characters are often compared to their fathers, while they possess traits similar to their mothers'.
However, unlike both the aforementioned characters, the One Piece manga has yet to reveal the identity of Monkey D. Luffy's mother. While the series did reveal that Luffy was the son of the rebel Monkey D. Dragon, the information came much later in the story.
With that in mind, Luffy never really interacted with his father, leading to their goals and legacies being vastly different from each other. They never truly interact or overlap with each other when it comes to their stories, all in all, making the father and son completely separate entities.
Therefore, Monkey D. Luffy is free from his parents' shadows. While the other characters do know that he is the son of Monkey D. Dragon, the mere fact has only really led to Emporio Ivankov befriending and helping Luffy during the Impel Down and Marineford incidents.
Besides that, Luffy also has the narrative surrounding the "D" clan, but that is not unique to him as there are several characters who have "D" in their names. Some of them are Gol D. Roger, Portgas D. Ace, Marshall D. Teach, and Trafalgar D. Water Law.
Hence, the only real legacy that is unique to Luffy is that he is the Sun God "Nika." He only inherited the legacy because he ate Hito Hito no Mi, Model: Nika Devil Fruit. Even in that case, for years, he believed what he had eaten was the Gomu Gomu no Mi Devil Fruit.
Therefore, unlike his Big 3 counterparts, Monkey D. Luffy did not inherit his parents' legacy but ended up forging his own. This is what sets him apart from both Naruto and Ichigo.
Related Links:
Boruto manga can never hope to surpass One Piece's success (and the read-counts shows it)
One Piece: Where would the Straw Hats Pirates be without Luffy, explored
Bleach TYBW: Why Yhwach called Ichigo his son, explained
9 Naruto characters who should have a Mythical Zoan Devil Fruit from One Piece