Susanoo has a brother and a sister: his sister Amaterasu is the goddess of the Sun, and his brother Tsukuyomi is the god of the Moon. You can read the story of Susanoo's quarrel with his sister Amaterasu here, and also about his battle with the eight-headed dragon Orochi.
You will meet the god Susanoo in the Week 2 Myth-Folklore Anthology story: The Eight-Forked Serpent of Koshi.
This carved screen shows Susanoo battling the dragon:
