Dark Magistar Templi Marbleis one of the main characters in the Adventure Time comic "Ice King". He is shown to be an antagonist who does evil deeds of varying levels.
He isn't actually "evil" but just lived a sad life in the search of fame. He attacked the Grand Master Wizard then hid away for years hoping his legend would grow. It did grow a little but The Dark Moon Esbats where the first to come seek him out, only to go threw his traps and fight him and win. He has a chance to fight them again but says he is too old to fight, but now his legend would live on after they tell everyone (which they didn't). He also celebrates Halloween.
He has Blue-green skin, he has a beard and hair of the same color, and only wears black robes. He has a pointy nose and ears.
His age is never officially revealed, however, he is very old.
First, I congratulate you young whipper-snappers. Very few have gotten this far into my chambers, without meeting death... or a much worse fate.
As for the legend of the dreaded and powerful Dark Magistar Templi Marble? Lies.
But finally! people came! So it really wasn't a life fully waisted!