To keep everything in one place, with what happened in Chapter 90, what does everyone actually think happened to Mika? To add in modified copy and pasted points:
First the nature of death in Seraph of the End, with vampires are they already dead? Using their powers, whether cursed gear related, or innate ones that come with being a vampire, people can recover from serious injuries/death. Looking at the situation, people could assume that with Mika physically incapable of being able to drink blood and recover, with Asuramamu's comment on the life force being gone, and of course an explosion, anyone could reasonably assume these would culminate in death.
And yet, after it was supposedly too late for Mika, he was shown to open his eyes. Vampires also turn to ash when they die, not explode - Yu however exploded when he turned into a seraph. With Krul not intervening, and with Asuramaru's comments on Yu to open his eyes and see what will happen, they likely know the true situation and so later chapters need to be awaited.
Yet everyone has their views on this, so processing what has happened, pointing out ways for or against what is at hand, this is the place to do it!