After a six-month pause, the highly anticipated return of the official One Piece anime brings us to the adaptation of the Egghead Arc. This futuristic setting is primed for a tumultuous conflict as the Straw Hat Pirates navigate their escape from Egghead Island, under siege by the relentless forces of the World Government, including the Marines, CP0 agents, and the Five Elders.
The narrative in the Egghead Arc centers on the World Government’s dark plot to eliminate Dr. Vegapunk. The story unfolds through a rich tapestry of dramatic flashbacks and real-time events. As Egghead transforms into a battleground, it is Sentomaru, Dr. Vegapunk’s devoted bodyguard, who confronts a profound existential crisis.
Disclaimer: This article contains significant spoilers from the One Piece manga up to chapter 1145.
The Existential Struggles of Sentomaru in the Egghead Arc
Sentomaru: The Diligent Guardian of Vegapunk

Sentomaru made his debut in the One Piece series during the Sabaody Archipelago Arc, where he faced off against the Straw Hat Pirates alongside Admiral Borsalino, also known as Kizaru. At that point, Sentomaru proved to be a formidable barrier for the Straw Hats, effortlessly countering Luffy’s attacks and sending him flying with relative ease.
His role intensified during the Paramount War in Marineford, where he commanded a battalion of Pacifista cyborgs against the Whitebeard Pirates and their compatriots.
Following a two-year timeskip, Sentomaru solidified his position within the Marines as Commander of the Navy’s Science Unit, reinforcing his long-standing commitment to being Dr. Vegapunk’s protector.

While Sentomaru’s claim of having the “greatest defense in the world” might seem exaggerated, his combat abilities are undeniably impressive. He employs sumo-style open-palm thrusts and can use his Armament Haki to inflict damage from a distance, negating the need for direct contact. Moreover, he can create defensive barriers with Haki to thwart incoming assaults.
His advanced Haki skills combined with proficient hand-to-hand combat mark him as a capable fighter. For instance, during the confrontations in the Egghead Arc, he successfully blocked an attack from Kizaru, although ultimately he fell to the Admiral’s overwhelming power.
Respect for the Straw Hat Pirates has always been prominent in Sentomaru, particularly after witnessing their growth during the timeskip. When CP0 launched their assault on Egghead, Sentomaru chose to align with the Straw Hats to combat their shared adversary and protect Dr. Vegapunk. Yet, this instinctive choice set him on a path filled with turmoil.
The Tragedy of the Egghead Incident

Initially uncertain about the unfolding events, Sentomaru chose to side with the Straw Hat Pirates, recalling his deep-seated loyalty to Vegapunk. However, this decision proved critical when Rob Lucci, aiming to undermine Sentomaru’s command over the Seraphim cyborgs, swiftly targeted him during the chaos.
With astonishing speed, Lucci struck Sentomaru, breaking through his defenses with a single, lethal blow. This devastating hit forced Sentomaru to the ground, enabling Lucci to seize control of the Seraphim forces.

Eventually regaining consciousness, Sentomaru sought shelter from his injuries. Determined to thwart the advancing World Government fleet, he activated the Mark III Pacifista stationed on Egghead, which compelled Admiral Kizaru to personally intervene and confront him.
Kizaru, despite showing signs of respect for his former ally, was forced to engage Sentomaru, ultimately incapacitating him with a powerful laser strike. Unconscious once more, Sentomaru miraculously revived in time to rescue Jewelry Bonney, who was thrown off balance by Kizaru’s attack.

In a bid to save Bonney from a devastating fall after Kizaru’s blow knocked her from Egghead’s Labophase, Sentomaru exhausted his remaining strength to catch her, but tragically succumbed to his own injuries shortly thereafter. Marine forces discovered him in a lifeless state, taking advantage of the moment to detain him.
Bound and vulnerable, Sentomaru’s fate took a shocking turn when Emet, the Iron Giant, unleashed a burst of Joy Boy’s Conqueror’s Haki, neutralizing the Marines. However, with Vegapunk now dead at the hands of Kizaru, Sentomaru found himself forced to flee Egghead, leaving him to weep silently as he rowed away from the island.
A Betrayal of Trust

The roots of Sentomaru’s unwavering loyalty to Vegapunk can be traced back to his childhood, as the scientist rescued him from a bleak existence. Banished by his community to the desolate Mount Kintoki due to his violent tendencies, Sentomaru encountered Vegapunk, who recognized his strength and invited him to be his personal bodyguard.
Close to starvation, Sentomaru accepted this position, viewing Vegapunk as his savior, and pledging to defend him at any cost.
Tragically, this dedication culminated in dire consequences when Sentomaru chose to battle on behalf of Vegapunk against the World Government’s might.
Unknown to Sentomaru, Vegapunk’s ultimate goal was to die by the hands of the World Government, catalyzing a pre-recorded message to be aired publicly.

Vegapunk’s request for Sentomaru to fight, despite knowing his fate, demanded that the loyal bodyguard recklessly put himself in harm’s way against formidable adversaries like Rob Lucci and Kizaru. By siding with Vegapunk, Sentomaru also forfeited his chances within the Marines, effectively becoming a target.
In this cruel twist of loyalty, Vegapunk exploited Sentomaru’s devotion, treating him as a mere pawn in his grand plan. Believing he was safeguarding Vegapunk, Sentomaru instead became a sacrificial piece in a game far beyond his comprehension.
Upon learning about Vegapunk’s demise, Sentomaru was devastated, oblivious to the scientist’s machinations. His ordeal did not cease with Vegapunk’s death, as the individuals he trusted continued to betray him.

Admiral Kizaru, although lamenting the necessity of his actions, wounded Sentomaru in the process, having been forced to confront his ‘nephew’ due to duty. Their bond, rooted in mentorship and admiration, faltered under the pressures of the conflict, culminating in Kizaru’s reluctant action against his former student.
In the chaos of the Egghead Incident, Sentomaru found himself abandoned by the very people he had trusted, including Monkey D. Luffy, who failed to fulfill his promise of protection for Vegapunk, leaving Sentomaru grieving the loss of his mentor.

Jewelry Bonney, although she showed concern for Sentomaru, did not mobilize a rescue, despite his sacrifice to save her. The satellites of Vegapunk appeared indifferent to his fate, leaving him to navigate his uncertain end.
Although Sentomaru may not epitomize the archetypal tragic character in Eiichiro Oda’s illustrious saga, his experience stands as a poignant testament to loyalty unrequited and the sobering reality of betrayal.
Ironically, Sentomaru’s trials began on a rare day off, underscoring the cruel twist of fate that plagued his journey.