A1) Izayoi (Inuyasha's human mother), she died while Inuyasha was still a kid; but unknown about how she died. But, first, in the beginning of the 3rd movie (Swords of the Honorable Ruler) when she's about to give birth to Inuyasha, Takemaru no Setsuna (a samurai who was in love with her and jealous of her love for the Great Dog Demon) killed her, but she used the last bandaged of her strength to give birth to Inuyasha, before she dies. After, the Great Dog Demon arrived, he found Izayoi dead, but he used the Tenseiga to bring her back to life. So, she can be alive again and; live long and well with InuYasha. And she was so alive when Inuyasha was still a kid and then later died.