Simca (シムカ, Shimuka), also known as Simca the Swallow (Tsubame no Shimuka, Simca the Swallow) and the "Migratory Bird", is the leader of the group. She is the twin sister of Kilik and a first generation gravity child. She was part of Tool Toul To until after Sleeping Forest is destroyed and eventually works under Nike. She takes great interest in Ikki, whom she believes is destined to one day become the legendary Sky King and holds feeling for him. She eventually has her hair cut short, abandons her usual care-free attitude, and focuses on strengthening Ikki, though she is soon attacked by Sleeping Forest and temporarily placed into a wheelchair. After Sora and Nike take over, she attempts to help Kogarasumaru enter the tournament, and she and Ikki promise to ride together afterward.