Riko Amanai’s death and the Hidden Inventory arc as a whole are a major turning point as far as the story of Jujutsu Kaisen is concerned. Had Toji not interfered with the causality of Tengen’s merger, had he decided not to kill Riko Amanai, had he decided not to accept the challenge of defeating a six-eyes and limitless user, then things wouldn’t have been as bad as they are in the Jujutsu Kaisen universe.
Geto wouldn’t have spiraled down to become evil, which in turn would have severely hampered Kenjaku’s ultimate plan too.
In short, everything bad that is happening in Jujutsu Kaisen right now can somehow be attributed to Toji killing Riko Amanai. And oh boy, was that a sucker punch to the gut!
However, why did Toji even take up the assignment to kill Riko Amanai? Let’s try to understand the motives behind this move!
Why did Toji kill Riko Amanai?
To answer in short, Toji killed Riko Amanai because he was hired to do so by the Time Vessel Association (also known as the Star Religious Group) and also to send out a message.
Toji didn’t have any personal enmity with Riko. He didn’t care if the merger with Tengen happened or not. For him, killing Riko was just a job for which he would be paid an enormous amount of money.
But, it was not all about money.
Toji’s reason to take up the assignment was very nuanced. He might have agreed to kill Riko in exchange for getting paid, but knowing that a strong sorcerer like Gojo was there on the opposing side appealed to his broken ideals and his pride.
Defying the Zenins who rejected him:
While accepting the job to assassinate Riko Amanai in chapter 66, Toji explicitly states that he went by the name Fushiguro, instead of Zen’in. This open defiance of his roots formed the crux of his decision to take up Riko’s assassination.
To know why he harbored a deep resentment towards the Zen’in clan, we just need to take a look at how they treated him.
Being affected by the Heavenly Restriction meant that Toji Fushiguro did not have an ounce of cursed energy in him. This made him the black sheep of the family. The treatment he received was much like Maki- looked down upon and discriminated against.
As Toji notes (chapter 113), the Zen’in clan was a useless place for someone without cursed energy. It wasn’t just the discrimination, Toji was also harassed a lot.
In fact, the official Jujutsu Kaisen fanbook states that the one thing that caused Toji a lot of stress was the Zen’in clan.
Going by Naoya’s monologue in JJK chapter 151, it is clear that everyone in the clan expected Toji to be this awful, pitiful person, whose existence would be defined by his supposed weakness – zero cursed energy.
Instead, I believe Toji chose to rise above the hate, and let his skills do the talking for him. And the Zen’in clan being the ones who valued sorcerers with cursed techniques a lot, the existence of a physically skilled person like Toji went against whatever they stood for.
Accepting him was never an option. The reason? Toji’s lack of cursed energy ensured that he would never be able to excorcise cursed spirits, something which was seen as vital for a sorcerer. It was because of this that he was ostracized.
The harassment made him leave the clan and drop the name. However, the way he was treated by them made him want to defy and destroy the Zen’ins. He wanted to go against everything that the clan represented and bring them down.
However, what the Zen’ins did was not any different from how any other powerful sorcerer families would have treated their weak. The Jujutsu Society as a whole was warped, as evident by the fact that they refused to grade physically gifted individuals like Toji.
We could say that Toji’s defiance was against the Jujutsu society as a whole. Against the powerful and gifted sorcerers. Basically anyone and anything that aligned with the warped outlook of the Jujutsu world.
JJK manga has consistently presented this narrative of people wanting to break free from the traditional mindset of the old. Toji’s arc wasn’t any different.
Bounty hunting was not just a way for Toji to make money. Killing sorcerers was his way of proving his point, his act of defiance against the status quo. The guy who was shunned for not having any cursed energy was now killing the ones blessed with cursed techniques and tons of potential.
When he got to know that Satoru and Suguru, two of the most gifted sorcerers of this generation, were guarding Riko. He was enticed by the opportunity to defeat them and show the world even a monkey like him could defeat the strongest duo.
On the surface it seems like him sending out a message to the Jujutsu Society and Zen’ins, but to be honest, it was more an act of self validation than proving a point to others.
And this becomes evident when Toji went beyond what was asked of him by the Time Vessel Association and instead decided to fight and defeat an awakened Gojo.
A case of petty pride:
When Toji left the Zen’in clan, he was an unstable person. However, he regained some normalcy in his life after he met Megumi’s mother (Megumama).
While he did have his resentment for the Zen’ins, he had decided to keep all that aside and live a normal life. He decided to leave his pride behind.
But when Megumama died soon after Megumi’s birth, Toji was pushed down a reckless path. That’s how he became the person we see in the Hidden Inventory arc. The petty pride that he once abandoned had come back.
When Toji encountered an awakened Gojo at the House of the Children of the Star, he usually would have ran away from the fight, saying that he never worked for free. Meaning, Toji was not the kind of a person who did anything more than what he was asked to.
However, he broke character there and decided to have another bout with the strongest sorcerer.
This was not done JUST out of a need to send out a message, to defy the Zen’ins and the Jujutsu world. But as I wrote before, it had more to do with Toji’s need for self validation. After all those years of being shunned and called worthless, he badly needed this win.
And who better to defeat than a sorcerer who had just awakened to stand at the apex of the Jujutsu world. Gojo was everything that Toji stood against. And he couldn’t help himself but go up against Gojo.
Defeating Gojo would help Toji reaffirm his worth to himself. The moment he decided to fight Gojo was the moment he had given himself in to his petty pride. And that was precisely when he lost.
It is here that we understand that Toji was a broken man deep down. All those years of abuse and harassment had left a scar and his recklessness one way or the other, stemmed from it.
So, in short, taking out Riko was not just motivated by the money for Toji, it was more than that. And Akutami has done a great job of very subtly relaying that in the manga.
We had to go deeper into his psyche, but yeah, in the end, the whole assassination had a lot more than money in it as far as Toji was concerned.