After some time going through Pietro's memories, he saw why he was worthy of the set. The life he passed, the death of his mother and father when he was just eight years old. He lived in the streets for two years until the day he was tested and selected as a mage.
So he was not a mage born in a heath family as most mages, just as Gremory, he was borning in the poverty. Lost their companions before getting the dictionary and now his life was going to end just because he was someone truly worthy.
'Life isn't fair.' Gremory thought while erasing his mind.