You do know that this manga is a lot older than Jagaaan, right? Hakaijuu released in 2010, and Jagaaan is from 2017 after this one was already in its final chapters.
Did you not read the first Doku Mushi? Mari is dead, her mummy was preserved by her father. It was shown quite a few times too. (unless that was a fake corpse, the cult used to control her father.)