User blog comment:Godisme/The Shooting Star Project (Zero Mix)/@comment-4006918-20121201223441/@comment-3143776-20121201224721

"I planned Grimmjow to die earlier, but when I drew it, I saw there was no emphasize at all, so I added activities to it...but he played more active part than what I thought.”

No confirmation of Grimmjow being dead, just sounds to me like he originally planned for him to die, but changed his mind.