Even as Gabriel received the Grimoire of Necromancy, he had only received two Spells and that too, low tier spells. According to Lira, it was because he wasn't strong enough to use more powerful spells and it was the Grimoire's way of protecting him.
However, with time, he realized that he needed a more powerful spell if he wanted to rob the Academy. He had no other choice but to request the Grimoire for more powerful spells.
That's where the cycle began... A Cycle where he started receiving more powerful spells. From that point on, he had become a Mid Tier Mage straight from Novice Mage and learned High Tier Spells of other Elements as well.
He couldn't have guessed just how much burden such a thing was placing on his body since he wasn't even aware of a phenomenon like that. As if to make things worse, he entered the Tower of Challenges where he had to use his powerful spells more often than not.
