What if a person called Hoid was the original bearer of Adonalsium.
Who long long ago wrote a story of a mischievous young lad called Midius.
One day the power invested into the book Hoid wrote, the mischievous character Midius jumped out and became independent. (Re: stealing himself was his 1st act).
Midius then devoted himself to Hoid when one day their friends tore Hoid a part in front of Midius, and to his suprise took up the parts of Hoid before disapearing. (16 parts)
Midius then changed his name to Hoid in honor of his mentor, and set about getting his mentor back.
Hoid could be 'extremely hard to kill', and 'cannot harm the living', because he was written that way.
Coomba98