Andre's ascent to the status of a Hell First-level Reaper wasn't solely due to his mentor; Andre was exceptional in his own right.
Making contracts with demons, he had a group of elite infernal soldiers and generals, all seasoned warriors.
In his previous life, he was even the King of Ande Kingdom, favored to some extent by fortune.
With such an identity coupled with the power base he'd built himself, Hell would surely seek to appease Andre, provided they weren't hell-bent on pursuing his transgressions.
For Andre, the position of a Hell First-level Reaper was merely a new beginning, given time, he was bound to rise to a higher rank among the Reapers.
Look at his royal sister Elusha; he had maneuvered for her as well. Why was Princess Elusha merely an Intern Reaper?
Whereas Andre was a Hell First-level Reaper?
Because Hell considered Andre to be much stronger than Elusha by more than a mere trifle.
