Kurome: Kurome is perhaps the member of the Jaegers that he is closest to. The two seem to stay with each other the most and over time he develops a rather strong and caring bond with her, to the point she confides in him her fear of being disposed of for being seen as weak in battle following injuries. Both are seen to get along quite well. He has silently declared that he'll protect her, having done so several times, such as taking a hit that would've proven fatal for her if it had impacted her. He is also very protective of Kurome and attacks Syura in a rage when the latter attempted to take Kurome as a sex toy. Over the course of the series, Wave appears to develop romantic feelings for Kurome. He cares for her greatly, most notably when it comes to her health. When Kurome went to confront Akame for a fight to the death, Wave was adamant about her leaving and was even going to stop her with force if necessary, but Kurome kissed him to distract him. That kiss made Wave realize his feelings for her, and declared his love for her after stopping the fight between the two sisters, even destroying Kurome's Teigu and defecting from the Empire with her.
Esdeath: He is respectful of his leader, but at the same time, is also terrified of her, especially when it comes to failing her. Esdeath has noted that she regards Wave as incredibly strong and talented, almost perfect. Wave appears to have great faith in Esdeath, and was relieved to have her back after a long absence.
Bols: Though initially frightened of Bols' outside appearance, Wave eventually formed a strong connection to Bols, and understood the man's gentle nature behind the mask. Wave was strongly affected by Bols' death and was later seen bringing flowers to his grave, as well as offering help to his family. Overall, Bols' death was one of the most memorable events in Wave's life, causing him to swear to avenge Bols during one of Night Raid's attacks and when he attacked Syura for killing Bols' family.
Run: As a fellow Jaeger, Run and Wave had a strong comradeship. Though not much was seen, the two had been shown to care about each other, with Run comforting Wave after Bols' death and holding him back from getting into trouble with Wild Hunt due to Syura being the Prime Minister's son. Run later revealed his past and true intentions to Wave. After witnessing Run turned into a corpse puppet, Wave was greatly saddened by seeing his friend reanimated and enslaved, wishing for him to rest in peace instead. Later, Wave started studying in order to carry on Run's hopes to change the Empire from within and to succeed them. Even after death, Wave kept thinking of how Run was still trying to help him and Kurome, and it was his feelings towards Run and Kurome that gave him the resolve to utilize Run's Teigu, Mastema, in combination with his Grand Chariot.
Seryu Ubiquitous: Initially puzzled by Seryu's cheerfulness, Wave at first came to befriend her enough to comfort her after Dr. Stylish's death. However, he became more hesitant towards her after the latter revealed her psychotic nature. It was actually Seryu's psychotic nature that made Wave question the nature of the Empire. He, however, still cared enough to try and avenge her death at the hands of Night Raid along with the deaths of Koro and Bols when they tried to kill Bolic.
Dr. Stylish: Initially frightened by his effeminate nature, he warmed up to the scientist enough to consider a him comrade.
Syura: Wave openly detests Syura, mainly due to Wild Hunt's methods in dealing with criminals, and Syura asserting himself due to his father, the Prime Minister. He was further provoked when Wild Hunt killed the family of deceased Jager, Bols, and when Syura harassed Kurome.
Tatsumi: While only seen briefly, Wave immediately warmed up to Tatsumi and liked him as he was the only other "normal" person in Jaegers and he saw a lot of himself within Tatsumi. After stopping the fight between Akame and Kurome, and Wave defecting from the Empire. Wave and Tatsumi spoke on friendly terms, complimenting each other's strengths and resolves, even admitting that they trust each other, despite being enemies.
Akame: His 1-1 skirmish with her resulted in them both ceasing hostilities to talk and discovery of their mutual bond to Kurome. However, Wave shocked Akame with his strong resolve to save her life while Akame wanted to end her suffering. When Wave prevails and ultimately saves Kurome, Akame looked at him in a very positive light and respects him as Tatsumi does, even more in debt to him for doing what she gave up on.