7

Why was 6 afraid of 7? Because 7 ate 9.

7 was the older sister of 6 and a domestic terrorist. When 6 and 7 were just young girls, 7 ate and killed their older brother, 9. This led to an irreperable familial rift which permanently estranged 7 from the rest of the family.

In her old age, 7 bombed an Aeternan government surveillance building, leading to her arrest by the Magarrish Guard and subsequent death in a Magarrish Military Tribunal. She was thrown in a ditch and left to rot, and was feasted on by Strange Things.