Konoha’s Monkey King

"The second question: why did Obito Uchiha kill his teacher, the Fourth Hokage, and Kushina?" Hiruzen Sarutobi looked grave. That night, it was not only the Fourth Hokage and Uzumaki Kushina who died. His wife, Biwako Sarutobi, had also been killed by Obito Uchiha while delivering Naruto and caring for Kushina after her birth, when Obito came to seize the Nine-Tails after its seal had weakened. After the Fourth Hokage's death, no one in Konoha was qualified to inherit the Hokage title.