Death
Michael hoped he would never need this Soultrait, but he prepared it nonetheless.
Switch Bodies was a powerful Soultrait with one major restriction. You had to possess two bodies to use it. That kind of restriction was not something most Awakened could fulfill. In fact, the Primal were probably among the only ones with the powers to use Switch Bodies. After all, to meet the Soultrait's condition, your other bodies couldn't be much different.
That condition was also why Michael had problems using Switch Bodies. The main body had several Divinities and different Soultrait Symbols as the secondary body, after all. Still, upon upgrading Switch Bodies to 10-Star, while also adding more than 100 traits of various Soultrait Symbols, Michael ended up with an immensely powerful Soultrait.