Fidel becoming mad wasn't because he turned into a lich, but rather because Sasha's first reaction when she saw him was surprise and the urge to flee!
Even though she quickly reacted and controlled her behavior, this still made Fidel extremely upset.
People said that liches don't have feelings, but Fidel had just completed the ceremony. His soul fire was seriously upset, making his mind act strange.
From then on, he wandered the northern part of the despair hills, turning into the infamous [Mad Lich].
...
After Marvin heard the story, he had felt a bit sympathetic. But when the character of the story was in front of him, it was quite difficult to control his feelings.
Fidel was definitely a different kind of Necromancer, as he had a good heart.
Marvin decided that he would help him the best he could.
Proposal?
Marvin thought and asked, "Wouldn't naturally grown roses wilt when in contact with negative energy?"