Black Star Relationship with Patti

Patti and Black Star seem to be good friends, both loving to joke around and play pranks on people. They often joke around together along with Kirikou and once, the two team up to ruin Liz's attempts to get a date, with the two bursting out laughing at the end. As Patti's skills in hand-to-hand combat becomes apparent to everyone, however, Black Star seems to treat himself as her senior, implying that Patti does not know how tough the world can really be. However, he respects her skills and her dedication as Kid's partner.

Black Star Relationship with Death the Kid

Black Star, at first, does not like Kid that much. Since Black Star's aim is to surpass the gods, Kid is a rival to him as he is a Grim Reaper, a God of Death. Black Star often challenges Kid and picks fights with him in order to beat him. Their two conflicting personalities also causes them to argue at times. However, mostly, they still get along reasonably well, and make a good team in battle. However, Black Star's jealousy of Kid's god-like abilities soon consumes him, which causes Black Star to goad him into fighting him, with Kid winning quite easily. After that battle, Black Star then starts to respect Kid a lot more as he begins to understand what he wants to do. He also respects him as Kid was the only one who took Black Star seriously and did not look down on him when he claimed to everyone that he will surpass the gods. He is grateful to Kid for helping him open his eyes to everything, and in return, he saves Kid from the insanity inside the Book of Eibon and vows to become stronger in order to help Kid maintain peace and balance in the world. Black Star is now good friends with Kid, with all signs of rivalry and hostility gone between them. Although their personalities are still rather different, they get along quite well, sometimes even engaging in friendly banter.

Black Star Relationship with Maka

Maka is one of Black Star's closest friends. They apparently know each other from childhood, since they had grown up together in Death City. Black Star likes annoying Maka and winding her up, but he still cares for her deeply. He never hesitates to come to her aid when she is in trouble, not even asking for thanks afterwards, and always offers his assistance in battle. He still respects Maka's wishes, and leaves her to fight alone if she wants to. Black Star also never forgives anyone who hurts her, shown when he swears vengeance on Arachnophobia for hurting Maka and in his fury at Crona for betraying her. He understands Maka well, and has faith in her, although he does not often show this. Although they are close friends, they do have their share of fights and arguments, since their personalities are often in conflict. There is an especially tense moment between them when they are training to achieve a Chain Resonance, when Maka loses her temper with him and the two end up fighting, which ends with Maka punching Black Star and running off, in tears. After, when they successfully achieve Chain Resonance, Maka asks Black Star to punch her since she had punched him back when they had been fighting. Black Star grins and says that he would not hold back. In the end, Black Star's punch sends her several feet backwards and into a dumpster. Despite being in pain, with a large bruise on her face, she smiles and the two make up. Black Star also respects Maka for her abilities, saying that she and Soul are capable of things that even he cannot do. He also envies her ability of Soul Perception.

Black Star Relationship with His Shibusen Soul

Their personalities are rather similar, both being very headstrong and stubborn, thus, they get along very well and enjoy each other's company, with the two exchanging a high-five almost every time they meet. The two once even try to fight as Weapon and Meister, but end up failing miserably. Despite this, they still decide to be friends. Black Star understands Soul quite well, and of his desire to protect Maka, and he acts more serious when such a subject arises. He also trusts Soul in keeping secrets from others. As both of them mature, their friendship does so as well, and Black Star soon begins to respect Soul's cool-headedness and sound judgement. However, they also begin to conflict, since their personalities are now more different, as Black Star does not agree with Soul in terms of keeping Mifune's death a secret to Angela. Black Star also admits that Soul, along with Maka, can be capable of things that even he cannot do.

Black Star Relationship with His Family

White Star

Black Star's father. Black Star does not know White Star personally, since he was killed when he was only a newborn. However, he bears no grudges against this as he knows that his father had been a criminal, and he had paid the price. However, White Star and the Star Clan's history is shown to be a source of insecurity for Black Star, and because of his father's actions, he is often ostracised by people victimized by the Star Clan. At one point, Black Star unintentionally begins to follow in his father's footsteps, becoming hungry for power and on the brink of following the 'Path of the Demon.' However, he soon realizes that this is wrong, and starts following the 'Path of the Warrior,' and he finally comes to terms with his heritage as the Star Clan, leaving White Star's influence behind him.

Mother

Not much is revealed about Black Star's mother. His opinion of her is the same as his father, that by being killed by the DWMA, she had paid for her crimes.