Tokyo Revenger's premise is not unlike many other time travel anime. Hanagaki Takemichi's time leaps and attempts at saving people, no matter how well-intentioned or how successful he manages to fix in the past, the future seems to be getting progressively worse every time he manages to fix the past. Which is to be expected considering there are many loose threads, and a lot of factors that take place over the course of 12 years. Despite all that, it is progressively crushing to Takemichi's resolve and psychological state, as through the course of three timelines already he has experienced and witnessed horrible things happen to his friends, leading to deaths that are all spearheaded by one rotten individual. However, to answer who that is, it depends on asking what factors would lead to the dark futures.
Tokyo Revengers as an anime premiered back in 2021, and had a massive following especially considering its Manga before was a popular shonen. The story grasped at people's attention, and in subtle, engaging ways. Its characters struck a chord with the readers, and especially their emotions as the heart-wrenching moments can be real. Despite all this, season 2 starts off on a rather somber and despairing note, with Takemichi's attempts at creating a better future worsening over the course of the arcs. As to why that is, it is heavily dependent on the characters and a few narrative factors. Even so, the audience themselves have been asking a common question. Why is the future worsening every time?
The Coinciding Factors
The story feeds us information as soon as possible about the cause of Tokyo Manji Gang's fall and the dark future involved, however there are a myriad of factors that occurred in the past and are to happen that may need to be considered to understand. Firstly, despite Kiyomasa's plan to eliminate Draken and therefore causing a rift in the Tokyo Manji Gang, this plan wouldn't have worked if it weren't for the fact that Moebius and the Tokyo Manji Gang battle wasn't orchestrated by a single individual. That individual in question managed to convince the leader of Moebius to aggravate the gang, causing a battle that leads to what happens. One of many factors that contributed to the dark future is found not just in this arc, but also in the following arc which explicitly states more information.
The Valhalla arc had introduced Baji as a factor in the story, along with a former member of the Tokyo Manji Gang, Kazutora; who had been involved in accidentally killing Mikey's older brother. However, the shadow leader of Valhalla, riled up not just Baji and Kazutora in Valhalla, but pit them both against Mikey in the following battle. Kazutora's single-minded grudge against Mikey, and Mikey's growing darkness and violent nature both collided in a fight that would have ended with Kazutora's death and a worsened future at the time. Thankfully, Takemichi managed to prevent that specific future, although it was only replaced with the worst so far. Aside from these factors being Mikey's darkness, and the grudge that other people had against him...who ended up being the one to manipulate all of this?
Kisaki Tetta
Even though every future is different in tragedy and consequence, the one consistent component of each of Tokyo Manji Gang's possible futures is Kisaki Tetta. Despite not knowing much about him at first, or even how he connects to Takemichi as a character, he himself has been responsible for almost all the manipulation and horrid actions in the story. He entered Moebius to manipulate it from the inside, and after its supposed defeat, with Draken's planned death he would have taken the position as Mikey's right-hand man. More consistently, he's always been the one in the future to plan and orchestrate hits and attacks on the main characters, goading them and planning to cut loose ends.
However, when Kisaki came into the limelight in the Valhalla Arc, his presence was felt even more in the story. Despite all that, the audience is assured that Takemichi time-leaped and stopped both plans from happening. Takemichi has intervened in the previous season, but the mystery surrounding Kisaki remains even now. The future worsens so long as Kisaki is around to persistently, almost obsessively, control the Tokyo Manji Gang with his influence. As to why exactly he is so persistent about wanting to have the gang under his control, that is left unanswered. However, this hasn't stopped many in the audience from enjoying hating Kisaki for his manipulations as the antagonist, or even just hating him in general because of his horrid involvement and the actions he has committed. Even so, Kisaki manages to do all this from the shadows, and without even revealing his intentions or having been kicked out from the Tokyo Manji Gang yet.
Even so, the second season may give us more insight as to what Kisaki plans to do this time. The future is still worsening at this point, but it can only be because of Kisaki Tetta's influence. However, as to what happens in the current arc that leads to the future seen at the end of season 2, that will need to be revealed in time as the season continues. Regardless, Takemichi has his hands full and an opponent he must soon face head on. If Kisaki Tetta's allowed to continue his hijacking of the Tokyo Manji Gang, then the future that Takemichi fights for, the friends and loved ones that he made along the way, as well as his own life, are doomed to fall into a deep pit.