Joe Final Moments
Internal Investigation Arc
Arc Info

Chapter 38 - Chapter 40

Arc Guide
"BREW" - The Tempest Arc
The Clown Arc

This page refers to events in the manga. For the similar story arc from the anime, please refer to Eibon Investigation Arc.

The Internal Investigation Arc is the twelfth major story arc in Soul Eater. It is also the first story arc diverging from the anime. Although both Eibon Investigation Arc and this manga-exclusive arc focus on Joe Buttataki's arrival to Death City, Franken Stein's madness from Marie Mjolnir's implanted snake, and Black☆Star's self-doubt following his defeat on Lost Island.

Featured DebutEdit





Part 1Edit

Joe Buttataki's arrival to the Death Weapon Meister Academy puts numerous members of the staff under suspicion of being a mole for Arachne. A reunion with his ex-girlfriend, Marie Mjolnir, confirms that indeed a traitor in within their midst, upon finding the snake within her that drove Franken Stein into madness.

Meanwhile, as Black☆Star confronts his mortality that results in a duel against Death the Kid, Maka Albarn makes a shocking discovery that Crona has betrayed Shibusen to Medusa.

Part 2Edit

As Maka struggles with knowledge of Medusa's survival and Crona's potential treachery, Kid struggles as well to approach a troubled Black☆Star in combat, eventually knocking him unconscious but morose at having to knock down his friend.

Meanwhile, Joe approaches Marie for a date, while warning her that his investigation suggests that Stein may be dangerous. Before he can make his date, Joe's investigation leads him to locate an actual mole within Shibusen, who kills him. Finding Stein's brand of cigarettes left at the scene of Joe's death, Spirit Albarn and Sid Barrett arrive at Patchwork Lab to arrest Stein for Joe's murder.


Spirit and Sid place Stein under arrest for the murder of Joe Buttataki—but with Mira Naigus and Marie, they expect he is innocent. Therefore, while Spirit, Sid, and Mira will report that Stein escaped, Stein and Marie will hunt down Joe's actual killer.

Meanwhile, Black☆Star and Tsubaki Nakatsukasa for Japan so he may improve his use of her Uncanny Sword Mode.

Finally, Maka wrestles with her knowledge of Crona's betrayal, and before she can approach them as a friend, she finds that Medusa has already left with them.

Notable InstancesEdit

  • Death is suspicious that there is a mole within Shibusen, based on how Stein fell into madness at the pivotal moment of acquiring BREW on Lost Island. Death therefore brings Joe Buttataki to Death City to conduct an investigation.
  • Background information is revealed about Marie Mjolnir, including her previous romantic relationship with her ex-boyfriend, Joe Buttataki.
  • Before Joe can rekindle his relationship with Marie and identify who implanted a snake within her, Joe is killed by another mole within the DWMA, leaving Stein accused of his murder.
  • The pressure of Joe's investigation troubles Crona. As Maka overhears Crona's admission of betraying Marie and Shibusen, she is too shaken to report Crona. Before Maka can question Crona herself, Medusa has taken Crona away from Death City, shocking Maka. Crona will remain an opponent to the DWMA until the manga's final arc, when they help defeat Asura.
  • Black☆Star's frustration with his failure on Lost Island leads him to challenge Kid to a duel to prove to himself that he is still on the road to becoming a god. Scared for his friend's injured soul due to his use of the Uncanny Sword Mode, Kid is forced to knock out Black☆Star, handing Black☆Star another defeat. This defeat motivates Black☆Star to leave Death City with Tsubaki to acclimate himself to the Uncanny Sword.

Differences from Eibon Investigation Arc and the AnimeEdit

  • The anime never reveals what Medusa was going to do with Crona upon the child's return to the mother.
  • By this chapter the anime had diverged widely from the manga. Whereas in this chapter Joe Buttataki's investigation into treachery within Shibusen leads him to suspect Stein, and to meet his death, in the corresponding episode Joe had only just arrived at the Academy, and his task was to create weapons from demon tools in the fight against Arachnophobia, not to investigate.
    • As the detective of the anime version of the Internal Investigation Arc, it is Death the Kid not Joe who is the investigator.
  • In the manga, Spirit Albarn and Sid Barrett arrest Franken Stein and instead of bringing him to Death takes Stein to Hook Cemetery to meet with Mira Naigus and Marie Mjolnir to see off him and Marie so they can clear Stein's name and find who really killed Joe Buttataki. In the anime, however, Spirit doesn't report Crona's disappearance to Death instead he informs his daughter and Soul about what had happened to Crona. This shows Spirit to be more cautious about reporting things to Death.
  • Whereas this arc refers to Marie and Joe as having dated, no mention of such a relationship exists in the anime.
  • However, the anime did give Joe a love interest: coffee. This arc does hint at Joe’s appreciation for a good cup of joe (perhaps related to his own name), yet the anime exaggerated his love for coffee whereas in the manga Joe simply dislikes the taste of what the Academy serves.
  • Whereas in the manga Black☆Star met with Naigus to receive the discouraging news about his health when using the Uncanny Sword, in Episode 38, this news was passed along to Tsubaki Nakatsukasa first, who then informed a truant Black☆Star.
  • As well, whereas in the manga Black☆Star challenges Kid to fight as soon as he exits the Dispensary, where Kid happened to be standing, in Episode 38 Black☆Star met with the main cast in the Class Crescent Moon, and it is at this point that he challenges Kid to fight.
  • According to the manga and this chapter, Maka had discovered Medusa's survival and Crona's treachery when she see's Eruka Frog speaking with Crona about Medusa's survival. While in Episode 39, Maka and Soul Evans learn about Crona's treachery when he/she confesses what had happened to Professor Stein in the desert pit. As well, Soul was not with Maka when Maka learns of Crona's treachery in this chapter.
  • Episode 38 concludes with Maka and Soul visiting Black☆Star in the infirmary to confirm his recovery, and Tsubaki meeting with Kid, as he repairs the Academy's spire, to apologize for Black☆Star's behavior. Neither event occurs in the manga: Maka retreats to her bedroom to ponder the news of Crona's treachery while Soul prepares a meal, and Tsubaki and Kid retreat into the background following Black☆Star's defeat.


  • Though the killer of Joe is eventually revealed to be Justin Law, this arc complicates when exactly Justin fell under the sway of Asura’s madness. Medusa first sensed this kind of madness in Chapter 31, “Reunion Express (Part 2),” upon her departure from Death City, which suggests Justin was mad comparatively early in the manga, before his attack on Lost Island but perhaps even before his rescue of Maka or his first appearance in the manga. *This arc hides the identity of Joe Buttataki's murderer. As later chapters explain, based on the presence of madness circling around Death City as Joe pierces through Medusa's soul protect, the murderer is Justin Law. Spirit claims Joe died from having his chest sliced open by a large blade. This detail is one of many that identify the guillotine Death Scythe Justin Law as Joe's killer. Chapter 41 has the Flying Dutchman and The Clown discuss how they "turn[ed ...] the other one," and the previous chapter had Joe seem to recognize his killer, which is appropriate for a Shibusen agent to recognize a Death Scythe. As well, in Chapter 38, Azusa Yumi had notified Joe that Justin was away from Death City on an assignment, which would allow Justin a temporary alibi.
  • Although Joe refers to himself as a former meister at the Academy and Marie's ex-boyfriend, whether or not he was Marie's meister is not made absolutely clear, although such evidence suggests he may have been her meister.
  • Joe's observation that Justin is not available to meet for interrogation hints strongly at his identity as Joe's murderer in the next chapter: Atsushi Ohkubo may have kept the character out of the chapter to throw off suspicion, and Justin may have feigned being elsewhere hunting for Asura so no one would know he was back in Death City to kill Joe.
  • Azusa's dialogue confirms that Kid's party for Crona at Gallows Mansion and his mission to retrieve the Eternal Spring take place on May 21, and that on the next day, May 22, Lord Death assigned Justin to hunt for the Kishin.
  • In the manga, Spirit’s remarks about Marie giving birth to the snake foreshadow her pregnancy in the very last chapter of the manga.
  • Although this arc is the first appearance of Deathbucks Coffee, better known in later content as Deathbucks Café, the location would not gain its more familiar form until Chapter 3 of Soul Eater NOT! where it would serve not only as a job but another major set for the series, introducing Tsugumi Harudori to the Thompsons and clarifying the process by which Shibusen students earn allowances.


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