Tsubasa comes from a long line of exorcists. He transferred to Sakura's high school in chapter 19, and like her, he can see ghosts—though his approach is pretty different. Instead of helping spirits find peace, he tends to blast them with sacred ashes, which often backfires by turning them into actual evil spirits instead.
He and Sakura actually met years ago, and once he realized she could see ghosts too, he developed feelings for her. After transferring to her school, he's been pretty relentless about trying to get her to return those feelings, especially since he's clearly jealous of how much time she spends with Rinne. That jealousy is what pushed him to start tagging along on their ghost-hunting runs in the first place. Hanging around them has gradually changed his perspective though—he's come to understand that not every ghost is a threat, and he's loosened up about which ones to exorcise.
He's quick to jump to conclusions, particularly anything involving Rinne and Sakura together. There are hints throughout the series that he's Christian, which ties into his exorcist background.
Content compiled by AnimeList.moe from publicly available sources.
