Life of crime
Rell had led a life of crime since his teenager years, and was arrested several times over many years. In 2012, Rell was hired by Calisto Yew to kill an employee of the Cohdopian Embassy, Deid Mann. If caught, he was to claim to be the Great Thief Yatagarasu. Sure enough, he was caught on camera committing the crime and promptly arrested. During his interrogation, he followed his orders, claiming to be the Yatagarasu. However, he did not recognize the Yatagarasu's signature calling card, making his claim suspicious.
Yew became Rell's defense attorney, telling him to accuse the presiding prosecutor for the case, Byrne Faraday, of being the Yatagarasu, in exchange for an acquittal. In court, because of the clear and decisive evidence against him, Rell confessed to the murder, but claimed that Byrne Faraday, the Yatagarasu, had told him to do it. After the subsequent uproar in the courtroom, court was adjourned and a new prosecutor, Miles Edgeworth, was summoned to replace Faraday.
During the intermission, Faraday dragged Rell to Defendant Lobby No. 2 to negotiate a deal with the defendant. However, Yew had planned to kill Faraday all along, and did so. She then had Rell put the surveillance video of Mann's murder into a VCR in the room before shooting him dead. Yew proceeded to modify the crime scene so as to give herself an alibi, throw off the perceived time of death, and made it look like the two men had killed one another. The bodies were later discovered just as the trial was about to resume.
Despite Yew's attempted cover-up, Miles Edgeworth slowly unraveled the various inconsistencies with the initially perceived crime scene. He eventually figured out that Yew was the true killer as well as the true Yatagarasu. However, before Yew could be arrested, she pulled a gun on Edgeworth and escaped in the confusion. Thus, Mack Rell's killer would not be caught for seven years.
Rell was a prolific criminal but also evidently a sloppy one, as seen from his many mistakes when trying to follow through on his last crime. He seemed to follow orders closely from those with more power than him, such as Yew.
- "Makari tooru" means "to let slide" or "to get away with" in Japanese.
- His English name is a play on "mackerel", but may also have come from his Japanese name.
- In the unofficial French fan translation patch, his name is "Tanguy Souroch", which is a play on the French proverb "Il y a anguille sous roche" (lit. "for there to be an eel hidden beneath a rock") equivalent to "something being fishy", "smelling a rat", or "something being afoot" in English.
- Rell was apparently modeled after the game's producer, Motohide Eshiro.