Space Mithril Soul
Some people are born with an exceptionally strong soul. It allows them to pull through intense and tough situations where a normal soul would usually crumble from the pressure. However, there is one type of soul that can withstand the body itself; capable to keep on going through sheer willpower even when bodily functions are falling apart.
He survived three heart attacks within two months before his body forced him to lay to rest?! Wow, he must have been granted a Space Mithril Soul by God.
(Plausible) CausesIt is still unclear what grants a person this type of soul. Many people, mostly priests of religion or researchers from universities, have been trying to provide an explanation to the common folk. While there is no truth, it does give people hopes of gaining a Space Mithril Soul.
Human BeliefAccording to the priests of monotheism humans, it is their God that grants people this soul. By showing that one has a strong soul already and using it for the right purposes, God can essentially upgrade the soul to become even stronger. Other believers of this religion think that they can make their soul stronger by praying to God and completing the tasks He has set of their lives.
Dwarfish BeliefDwarfs, on the other hand, believe that Vanhu, the Deity of Folk, gifts people with this soul.
I will bestow this gift upon those destined to be the hardiest of folk. They are born for survival and to protect those around them with an exceptionally strong heart and will as grave events are looming on the horizon.