- Tsukasa is an only child. As such, he is heir to the Suou family, an old military lineage.
- In several stories, Tsukasa states that his parents are often busy, so he has grown up mostly interacting with his servants. However, he is also shown to care for his parents deeply and greatly respect their expectations for him.
- Tsukasa has described his family as "poor nobles." Though quite wealthy, their nobility largely stems from their long family history, and they lack the profitable business ventures of families like the Himemiyas and the Tenshouins. One of Tsukasa's goals is to expand their sources of income, so that they don't "fall behind" other families.
- Tsukasa describes his parents as quite strict, and he often mentions being scolded for careless or childish actions. However, in Requiem, we also learn that Tsukasa's father went through a period of rebelliousness in his youth and that he greatly values Tsukasa's independence, allowing him to attend Yumenosaki without resistence.
- At the end of Requiem, Tsukasa has become the temporary head of the Suou family while his father recovers from illness.
As the heir to the Suou family, Tsukasa had a privileged but also rather strict upbringing. He was childhood friends with Tori Himemiya, who he often fought with. As children, Tsukasa sought the approval of adults by diligently trying to meet their expectations, while Tori shamelessly pursued his own interests and was regarded less favorably. This caused tension between them, but Tori's expressions of pity toward Tsukasa would also inspire Tsukasa to reflect on his own priorities.
At some point before entering Yumenosaki, Tsukasa had an experience upon getting lost in the city. He wandered into different buildings, overwhelmed by experiences unfamiliar to his sheltered upbringing. After finding himself in a bar, Tsukasa came across a former idol, a retired member of Backgammon who sang of his regrets and warned Tsukasa not to wind up like him, a pitiful man who had betrayed his friends. Later on Tsukasa would consider this experience a life-changing one. He listened to the retired idol's CD when the pressures of being raised as the Suou heir caused him pain and self-doubt. Tsukasa suggests that this experience inspired him to take control of his future and pursue his own interests, which would later bring him to Yumenosaki Academy, and to Knights.
Tsukasa visited Yumenosaki, along with Tori Himemiya, when they were in middle school. During this visit, Tsukasa came across the remaining members of Knights left after Leo's departure. The three of them were practicing around the school's cenotaph, and although they seemed exhausted and quarrelled with one another, Tsukasa was drawn to the prideful way that they sang. This experience is what inspired Tsukasa to join Knights the following year.
Last Year (Enstars! Era)
See: Appears InInformation about what the character did during the Enstars! year.
Current Year (Enstars!! Era)
See: Appears InInformation about what the character did during the Enstars!! year.
After Repayment Festival, Tsukasa has succeeded Leo Tsukinaga's position as the leader of Knights. At this time, he is also acting as the head of the Suou family.