Maya Yotsuba, their aunt and the current leader of the Yotsuba Clan, was the reason Tatsuya was born with the unique magic to decompose, reconstruct, and detonate matter along with some gene manipulation.
Tatsuya steps in and explains it was a flash spell and talks them into accepting it was all a misunderstanding.
Tatsuya, , and are substituted in as players after No Head Dragon injures the original First High team for the Monolith Code competition, and under Tatsuya's leadership they are able to win first place.
Observing the pair is Shizuku who is joined by Kanou in the bath.