Tom Ksaver

Name: Tom Ksaver

Gender: Male

Birthday: July 5

Height: 169 cm

Weight: 75 kg

Affiliation: Marley Warrior Unit (Warrior program, non-combat researcher)

Occupation: Titan researcher, Warrior (Beast Titan shifter)

Titan: Beast Titan (c. 828–841)

Voice actor (anime): Kenji Hamada

Tom Ksaver is the former holder of the Beast Titan and a Marleyan Warrior of Eldian descent.

Outwardly mild and unassuming, he is in fact one of the most important intellectual figures behind the series’ lore, laying the groundwork for Zeke Yeager’s euthanasia plan and discovering a countermeasure to the Founding Titan’s Vow of Renunciation of War.

He appears first in Grisha Yeager’s memoirs as a man who calls out to a young Grisha on the street, and later is fully introduced in the Marley arc through Zeke’s recollections.

Zeke affectionately calls him “Mr. Ksaver” and later “Father,” and keeps his glasses as a cherished memento.

Ksaver is a gentle, soft-spoken man who almost always wears glasses and carries himself with a calm, slightly weary air.

Although he belongs to Marley’s Warrior Unit and holds one of the Nine Titans, his true passion is scholarship, not battle.

He is driven by curiosity about titans, approaching them the way Hange Zoë approaches titan research inside the Walls: as a mystery to be understood, not just a weapon to be wielded.

This inquisitive nature, combined with his non-threatening demeanor, makes him easy to trust—especially for a lonely child like Zeke.

Despite his kindness, Ksaver is deeply scarred by guilt and grief, convinced that his own existence and the existence of Eldians bring only suffering.

This internalized despair feeds into his eventual support for Zeke’s idea that Eldians should be peacefully removed from the world by making them unable to have children.

Early life and family tragedy

Ksaver is an Eldian living under Marleyan rule.

At some point before the main story, he hides his true Eldian identity and marries a Marleyan woman, with whom he has a son.

When his wife discovers that he is actually an Eldian, she realizes that her relationship with him—and their child—constitutes a severe crime in Marley, one that could bring punishment on her entire family.

Crushed by fear and shame, she attempts and succeeds in a murder–suicide with their son, leaving Ksaver alone.

This loss devastates him.

Haunted by regret and self-loathing, he throws himself into titan research and eventually chooses to become a Warrior and inherit the Beast Titan, describing this choice as a kind of “luxurious suicide.”

Becoming a Warrior and Beast Titan inheritor

Despite being a civilian researcher and not a front-line fighter, Ksaver is allowed to inherit the Beast Titan from its previous holder, likely because the Beast Titan at that time is considered relatively useless in battle—only somewhat larger than a normal titan, with little strategic value.

Marley grants him the power largely in recognition of his scientific achievements and to aid his titan research.

His Beast Titan form has the head of a ram, with thick fur covering the head and lower body.

While it has enough raw power to send other titans flying with headbutts, it is regarded as militarily unimpressive compared to other Nine Titans, reinforcing Ksaver’s status as a non-combatant.

Meeting Zeke Yeager

Ksaver often spends his free time playing wall ball by himself—throwing a baseball against a wall and catching it.

During one of these solitary games, he encounters young Zeke Yeager, who is struggling in the Warrior training program and is neglected emotionally by his parents, Grisha Yeager and Dina Fritz.

They begin playing catch together, and this simple game becomes the core of their bond.

For Zeke, Ksaver becomes the father figure he never had: someone who listens, encourages him gently, and spends time with him without demanding results or political devotion.

Zeke’s parents pressure him heavily to excel as a Warrior candidate so that he can support their Eldian Restorationist cause.

As Zeke’s grades and performance lag behind, Grisha and Dina become harsher, and Zeke feels increasingly cornered and unloved.

The turning point: betrayal to save Zeke

One day, Zeke overhears that Eldian Restorationists are about to be exposed by the Marleyan authorities.

He realizes that if his parents are caught, he will likely be sentenced to “paradise exile” as a mindless titan on Paradis Island.

In tears, Zeke confides everything to Ksaver: the Restorationist conspiracy, his parents’ actions, and his fear of being turned into a titan.

Zeke resigns himself to his fate and says that, even if he becomes a titan, he will not forget Ksaver.

Ksaver wrestles with the moral weight of what he must do.

Eventually, he urges Zeke to report his parents to the authorities, arguing that Grisha and Dina have used their son for their own cause without truly loving him, and that betraying them is the only way to save Zeke and his grandparents.

Following Ksaver’s advice, Zeke turns in his parents.

This act is seen by Marley as a proof of absolute loyalty, and Zeke’s standing and prospects as a Warrior candidate dramatically improve.

Planting the seed of the euthanasia plan

Years later, as Ksaver’s 13-year shifter term nears its end, his health begins to fail.

He can barely play catch with Zeke anymore, but he continues to share his research findings with him.

He reveals a key discovery: the Founding Titan does not only manipulate the memories of Eldians (the “Subjects of Ymir”) but can also alter their very biology.

This means that, in theory, the Founding Titan could change Eldian bodily structures so that they lose the ability to reproduce.

Hearing this, Zeke asks if the Founding Titan could be used to make all Eldians unable to have children.

He reflects that perhaps Eldians should never have been born in the first place, given all the suffering tied to their existence.

Ksaver, already burdened by his own past and convinced that Eldian life brings only pain, is moved by this idea.

He confesses that he has seen Zeke as a surrogate for his dead son and that he has long believed he himself should never have been born.

Zeke then promises Ksaver that he will use the Founding Titan’s power to free the world from the fear of titans and free Eldians from their suffering by ensuring that no more Eldians are born.

Together, they crystallize the core concept of the Eldian euthanasia plan.

Passing on the Beast Titan

Approximately twelve years before the Marley arc, Ksaver’s remaining term as a titan shifter ends.

As is customary, his titan power and memories must be passed on to a chosen successor.

Zeke is selected to inherit the Beast Titan.

Ksaver allows himself to be devoured by Zeke’s titan form, dying in the process and transferring the Beast Titan and its accumulated knowledge to him.

From that point on, Zeke carries Ksaver’s glasses as a keepsake and adopts a combat style heavily influenced by their shared games of catch, using precision throwing with rocks or explosives as his primary attack.

When Zeke inherits the Beast Titan, he addresses Ksaver as “Father,” confirming the depth of their bond.

Role in the battle of Heaven and Earth

In the final stages of the story, during the apocalyptic clashes often referred to as the battle of Heaven and Earth, Ksaver appears among the manifestations of past Beast Titan inheritors created by the Founding Titan’s power.

Initially, he and the other past shifters are essentially puppets controlled by Eren Yeager, fighting against Armin Arlert and his allies.

However, once Zeke’s consciousness reaches the Coordinate and he is persuaded by Armin to abandon the euthanasia plan and aid in stopping Eren, Ksaver and other past shifters respond to Zeke’s will.

Ksaver regains control of his ram-headed Beast Titan and cooperates in the effort to kill the Founding Titan and end the Rumbling.

During this battle, the full appearance of his Beast Titan form is shown properly for the first time.

After assisting in the struggle against Eren, Ksaver’s manifested titan body is erased when Armin transforms and detonates as the Colossus Titan, destroying the Founding Titan’s core.

Beast Titan

Name: Beast Titan

Inheritance period: Around year 828 to 841

Successor: Zeke Yeager

Ksaver’s Beast Titan differs from Zeke’s famous ape-like form.

His titan has the head of a ram, with horns and a heavily furred head and lower body.

It possesses considerable physical strength: its headbutts can send other titans flying.

Despite this, Marley evaluates it as tactically inferior and relatively unhelpful in conventional warfare, especially compared to titans like the Armored Titan or the Colossus Titan.

Because the Beast Titan of his era is treated as only a slightly oversized titan with no standout war function, Marley allows a non-combatant researcher like Ksaver to inherit it.

He himself admits that he is not very useful in battle and that he took the power mainly to further his research and, on a deeper level, as an elaborate form of self-destruction.

Scientific achievements

Near the end of his life, Ksaver publishes what is described as the “culmination” of his research.

Among his most critical findings is that the Founding Titan can rewrite not just the memories but also the physical structures of Eldians.

This discovery is the key theoretical basis for Zeke’s euthanasia plan, as it suggests that the Founding Titan could sterilize all Eldians simultaneously.

Additionally, Ksaver passes on to Zeke crucial knowledge about how to circumvent the Vow of Renunciation of War, contributing to the strategic framework that later allows Zeke and Eren to cooperate inside the Coordinate.

Zeke Yeager

Zeke is the central person in Ksaver’s later life.

To Zeke, Ksaver is far more than a superior or teacher—he is the first adult who shows him unconditional care and attention.

Their relationship is symbolized by playing catch with a baseball, which becomes both a form of emotional support and the training ground for the throwing skills Zeke later uses in battle.

Zeke’s decision to betray his parents, his adoption of the euthanasia ideology, and his entire identity as the Beast Titan are all directly shaped by Ksaver.

After inheriting the Beast Titan, Zeke begins wearing Ksaver’s glasses.

He also frequently uses baseball metaphors and throws projectiles with inhuman precision, reflecting Ksaver’s lasting influence.

Grisha Yeager and Dina Fritz

Although Ksaver never has a close relationship with them personally, Grisha Yeager and Dina Fritz are central to his impact on the story.

He is the one who advises their son Zeke to turn them in as Restorationists, indirectly leading to their exile: Dina becomes a Pure Titan on Paradis Island, and Grisha is pushed onto the path that will eventually make him Eren Yeager’s father and the final inheritor of the Attack Titan and Founding Titan before Eren.

Ksaver also appears briefly in Grisha’s childhood memories as a man who warns a young Grisha on the street to be careful, hinting that their paths cross long before the main events.

His wife and son

Ksaver’s unnamed Marleyan wife and their son exist only in his recollections, but their fate defines his worldview.

Their deaths convince him that Eldian existence is a curse, hardening his belief that the world would be better if Eldians were never born.

This personal tragedy is the emotional core behind his appeal to Zeke and his acceptance of the euthanasia plan.

Without this backstory, Ksaver would likely have remained a pure researcher instead of becoming the ideological architect of a global-scale solution.

Ksaver’s defining line, “In the face of the mystery of titans, hatred and conflict are trivial,” encapsulates his perspective.

To him, the phenomenon of titans—and the suffering intertwined with Eldian blood—is so overwhelming that ordinary conflicts seem meaningless.

His baseball motif and ram-headed titan form set him apart visually and thematically from other shifters.

Where many Warriors are raised as soldiers, Ksaver is a scientist first, titan shifter second, and reluctant Warrior most of all.

The glasses Zeke inherits from him symbolize knowledge, mentorship, and the burden of ideology passed from one generation to the next.

Every time Zeke appears with them, Ksaver’s presence and legacy quietly linger in the background.

Ksaver’s character design and concept are modeled after film critic and writer Tomohiro Machiyama, who worked on the live-action Attack on Titan film script.

His birthday, July 5, is the same as Machiyama’s, and some fans jokingly nickname him “Machiva-san” in reference to this inspiration.

Within the anime, another character named Tom appears earlier: a trainee soldier during the Trost District defense, voiced by Seiyuki Suzaki, who runs out of gas and dies after being eaten headfirst by a small titan.

This Tom is unrelated to Tom Ksaver, though the shared name has caused occasional confusion among viewers.