The Dark Magus, Raze Cromwell, was an old man when he perished—he was 76 years old, and his body was already deteriorating quicker than most.
There were perhaps countless reasons for this.
For the last ten of his years, he had spent them as the Dark Magus. Perhaps during that time, he had put his body through too much with the countless experiments, especially those revolving around Dark Magic.
Another reason could have been the countless fights he had with the Grand Magus.
The Magus title, in the first place, was only referred to those at the very top. The Dark Magus had gotten his name because, in a way, even the public had to admit that he was worthy of standing side by side with them, only he was on the other side.
The side of evil, or the bad, compared to the Grand Magus.
"Anyway, let's get ready to head to the meeting place, and remember what I asked you before.