Sphere[]
Rudo initially used to live on the Sphere as a Sphereite but grew a deep rooted hatred for it and it’s people after his foster father Regto who had raised him all his life was murdered at the hands of the Angel, despite this it was Rudo himself who was accused of the murder and sentenced to be thrown into the Ground as punishment, what further fueled his rage was Chiwa, who was the only person of the Sphere that Rudo had initially cared about but during his sentencing she had given up on Rudo believing that he actually had committed the murder, before falling he swore that he would return and kill every last person on the Sphere,[1]
Sphereites[]
Regto[]
At some point before the start of the story Rudo's father was thrown into the Ground and was abandoned as a kid. Then after he met Regto and was taken in, Regto filled the position of a foster parent ever since. Though he has no small familial affection towards Regto, Rudo also feels he is beholden to Regto for raising him. Consequently, Rudo goes around the city to hunt for salvageable trash and earn money to support the family despite Regto disagreeing with his criminal methods. However, after Regto was murdered by an unknown assailant he is seen by the public as Regto's murderer.[1]
Chiwa[]
Rudo used to have a crush on Chiwa, and Chiwa seemed to show signs to reciprocating his feelings. However, when Rudo was convicted of Regto's murder and he turns to her for her support against the claims, he sees Chiwa losing her trust in him and believes him to be a murderer. From that moment on, their special connection was lost and apparently she is now also one of the people Rudo vows to "send to hell".[1]
Ground[]
Rudo used to believe that the Ground was nothing more that a giant trash heap like the other Sphereites[1] but his expectations were subverted after he was thrown in and realized that there was a whole human civilization on the ground much like that of the Sphere,[2] he originally had to bear the hatred people of the ground had against him but joining the Cleaners helped him become more accustomed to the ground and it’s people.[3]
Cleaners[]
Rudo originally had no interest in the Cleaners and only became associated with them because Enjin roped him into it and he believed that he could help them out until he could find a way to get back to the Sphere,[4] but he was able to grow past the him that only knew to let out his anger on others thanks to the Cleaners and now sees them as friends who he can trust as they were the only people other than Regto who saw him for who he is and not simply as the son of a murderer or Tribe folk like the people of the Sphere did.[5]
Enjin[]
Rudo met Enjin right after falling into the Ground,[6] Enjin was amused by seeing how he would manage to escape from a bunch of slave traders,[7] after that incident he took Rudo with him and made him a new member of the Cleaners from the Ground.[8] Since then, they have a close relationship, with Enjin acting as Rudo's mentor and an older brother figure often giving him reassurance, giving Rudo some advice about his position and how to use his powers as a giver. Right after beating up Amo; Rudo and Enjin share an honest and deep talk in which Rudo opens up and confesses his fear of not being capable of changing as a person, and Enjin gives him advice and his support, offering his help to make him grow and mature.[9]
Zanka Nijiku[]
Initially, Zanka harbored a significant dislike for Rudo, believing he was attempting to steal his vital instrument [10]. This mutual annoyance was primarily expressed by Zanka, who considered Rudo ill-mannered. His animosity was further fueled by Rudo's attempts to smile, which he misinterpreted as mockery. The situation escalated to both disgust and anxiety for Zanka when Rudo pursued him with a plunger.
Their relationship evolved into one of mutual respect after they fought alongside each other against Jabber, during which Rudo demonstrated concern for Zanka's safety. Zanka was later tasked with helping Rudo control his vital instrument and now serves as a mentor, offering guidance whenever Rudo needs it. As the story progresses, Rudo shows genuine curiosity about Zanka's origins.
Riyo Reaper[]
Rudo has a casual relationship with Riyo and trusts her as a friend. At first, Rudo seemed startled every time Riyo showed her friendliness to Rudo, overtime Rudo acknowledged the sympathy the Cleaners expressed to him and consequentially became very fond of Riyo and cared for her safety and well-being. This can be seen when Rudo expressed anger at Kuro who got her hurt[11] and made him apologize to her for doing so.[12]
Amo Empool[]
Rudo and Amo's relationship began on a tumultuous note during the Lady of Penta Arc, with Amo initially acting as an antagonist. She used her Jinki to manipulate Rudo into a fierce confrontation with Tamsy and Zanka. Once the hypnotic spell was broken, Rudo, consumed by rage, would relentlessly attack Amo, only to be held back by Enjin and the other Cleaners. Following a crucial pep talk from Enjin, Rudo and Amo were able to reconcile.
Their bond deepened significantly when Rudo became one of the key figures in rescuing Amo from her kidnapper, Tamsy. Upon her awakening, Rudo's relief was palpable and sincere; he even presented her with a tulip as a "get well" gift, a small but meaningful gesture. In recent events, Amo's strong attachment to Rudo is undeniable. While the exact nature of her feelings—whether romantic or otherwise—remains to be seen, it's clear she considers him a profoundly special person. Rudo, in turn, demonstrates genuine and deep-seated concern for Amo's well-being. He becomes visibly worried when she is in any danger and is quick to show immense fits of rage whenever she is threatened, doing everything in his power to protect her.
Gris Rubion[]
Rudo's relationship with Gris began when Riyo presented Gris as a member of the Cleaner's supporters[13], although Rudo didn't get to know a lot from him from their first interaction, their friendship deepened when Gris was seriously injured in their confrontation against Jabber Wonger[14]. On a spur of the moment Rudo used Gris's "Hamsa" (an amulet which he used to pray for everyone's safety) to defeat Jabber, after the whole situation Rudo was filled with sadness knowing that not only he destroyed Gris's amulet but that he also presumably died due to his injuries, Rudo later on found out he was fine. Gris not only served as a big stepping stone into Rudo's fondness for the Cleaners but he also serves as an example of who Rudo should look up to[15]. Rudo looks up to Gris as a role model for how to behave and act towards others by showing them kindness,[15] and avoid being his old impulsive self.[16]
Rudo Surebrec's feelings for Gris Rubion are a complex blend of admiration, gratitude, and profound relief. Initially, Rudo looks up to Gris as a positive role model, appreciating his kindness, resilience, and unwavering commitment to others. This admiration intensifies after Gris's self-sacrificial act of protecting Rudo and Follo, which deeply impacts Rudo, leaving him consumed with sadness and guilt over the broken amulet and Gris's presumed death. Upon discovering Gris is alive, Rudo's sorrow transforms into immense relief and joy. He becomes incredibly grateful for Gris's support and comforting words, which significantly boost his self-confidence. Gris's actions solidify Rudo's view of him as a true team member and someone who embodies a valuable philosophy: that the worth of an item is measured by its ability to help others. Rudo internalizes this lesson, learning that true strength lies not just in physical ability but in courage and a compassionate heart.
Follo Tunito[]
In the Information Broker Arc, Follo and Rudo's collaborative efforts to thwart Kuro by impersonating each other were initially effective. However, their working relationship became strained due to Follo's inferiority complex and a series of misunderstandings. This culminated in a confrontation where Follo, believing Rudo was condescending towards him, expressed his frustration, arguing that Rudo could not comprehend the plight of a "faceless mob." Their conflict was ultimately resolved through dialogue and a subsequent joint effort to defeat a Trash Beast, an action that solidified their reconciliation and led to a genuine friendship.
Raiders[]
Rudo's relationship with the Raiders is mostly through the Watchman Series and his connections to the Sphere.
Zodyl Typhon[]
Jabber Wonger[]
Others[]
Kuro[]
After the Information Broker Arc, Kuro's involvement is less prominent, though he assists Rudo in transforming the box into a Vital Instrument. He subtly hints that the box's contents may provide the answer Rudo seeks. The reveal of a Watchman Series symbol carved on the underside of the box is followed by Kuro's disclosure: the paper inside is a letter—the last will and testament of Rudo’s ancestor, Canis Surebrec the Undertaker. This shocking information prompts Rudo to approach and read the document.
In a later scene, after a chase, Kuro gives Rudo intelligence on Amo's whereabouts and the choker maker's identity. Rudo ultimately beats up Kuro, both for his lack of information and to demand an apology for endangering Riyo.