Tsukiya Chabashira's Links
Starting out as best friends, they were inseparable. They shared a love for street racing, and shared a similar greaser fashion. However, their relationship fell apart after Hayabusa was picked for the academy over him. Tsukiya, believing the title was stolen from him, began antagonizing his former friend. This all came to a head when Tsukiya cut the brakes in Hayabusa's car before a race, resulting in Hayabusa's accident that almost killed him. Throughout the game, the two mend their relationship and seem to be on good terms until Tsukiya's killing. After all is set right, Hayabusa scouts out Tsukiya in an attempt to mend their friendship, and the two would go on to start a romantic relationship.
Much like with his mothers, his relationship with Sora is strained. He feels embarrassed being the only member of his family without an Ultimate title, and thus he often treats her with snide comments and rude remarks, laced with jealousy.
Tsukiya was often more of an older brother to Yuuki than Hayabusa was. He was always treating them with kindness and respect when he came around to hang out with Hayabusa. After his falling out, they still kept them close. However, he began to feed into their hatred and jealousy of Hayabusa, making them more aware of the supposed favoritism he got from their moms. Still, he cares for him deeply, and their death led them to a breaking point to try and end the game, even though it cost him his life.
Mari is one of the only bridges between Hayabusa and Tsukiya remaining. Friends with both of them, she chooses to stay neutral on their dispute. This does, however, puts her in many situations of having to deal with the two complaining about one another in quick succession.