User blog comment:JacobKyleF/PE Proposal: Grandfather from K.N.D./@comment-24439896-20200111003149/@comment-27599496-20200111033924

The setting isn't the issue, because Adventure Time is also extremely comedic and silly, and yet the Lich was accepted as pure evil.

The thing with Grandfather is that as big of a threat and as evil as he is, he's also played for laughs sometimes.