Master Glizzard

Master Glizzard is the 489 year old mentor of Huey and Luey. Originally known as the brothers' hometown clown, with an affinity for Gōrudengurahamu, a sugary wheat treat. Master Glizzard revealed himself as a talented and experienced assassin of the unknown S class (a rare class outside of the normal hierarchal class system). The reason for his high ranking is shown to be his use of the Ji Fōrzu, which gives him outstanding performance and quality in battle. He trained the brothers in the art of both murder, and glocal propaganda, a useful skill during their revolutionary struggle against King Terry. In the Season 2 mid season finale episode "Kurinji", Master Glizzard was killed in cold blood at night by Duey. Master Glizzard's "spirit", a black blob engulfed in white flames, flew off into the night. This "spirit" was never seen again, although some people assumed that the "spirit" would come back. These hopes for the "spirit" to come back were destroyed when the series was discontinued.

Future Theory
Throughout the anime, there are multiple references to Master Glizzard being from a far away land. Declaring he misses his friend from the old country, Burgzman (rough translation). However, during later events, many in the S3K community have theorized Master Glizzard is from the future. Originally speculated due to his eccentric language, making loud odd noises when something is good. However the main theory appeared when The Ghost, the monstrous spirit which possessed Duey, was directly connected to Master Glizzard's spirit through appearance.

After Luey's sword, The Foreskin of Jesus (rough translation), kills King Terry, the connection of ascension and descension (in terms of planes of reality) causes a rift in time and space. During this sequence, Master Glizzard's spirit is seen being flung into the future. The previous rift in reality (one epoch before the start of the story) which created The Foreskin of Jesus, is told in flashback as having a man and spirit emerging from it, and because the spirit is implied to be The Ghost, the man can be assumed to be Master Glizzard, who would therefore be from the future. This also implies that The Ghost is a paradoxical being, which travels into the future and then back to the past in order to have reached the future in the first place.

Many theorists have considered that The Ghost was a metaphor for war as a concept, making much of the conflict with The Ghost ironic and ultimately purposeless.

Trivia

 * Master Glizzard was offered a position as a member of the Legend League (リーグ・オブ・レジェンズ), it is unknown if he accepted the offer.