Clockwork
When his mother dies, Aizawa Shouta takes his brother Izuku to live with him. However, between dealing with the grief and Izuku starting at UA, they don't have much time to spend with their secret family...
...who decide to invade on the third day of school.
Or:
Inko dies, Aizawa and Izuku are brothers (and related to half of the League), Class 1-A finds out about the first half and Tenko is VERY protective of his younger brother.
