What is the significance of the symbol on Kevin Matchsticks tshirt in the comicbook Mage?

In the first series we find that Kevin is king Arthur, in the second series we find that he is actually the first hero of fiction Gilgamesh or perhaps Simply the archetype of the Great Hero. No matter what other mythological reincarnations we are introduced to Kevin seems destined to be the greatest. The Thunderbolt is a common symbol of the hero and representative of power. Kevin discovering his power in the first series, and coming to understand it in the second series being the major themes of the story. His thunderbolt symbolically represents his singular destiny.....That and Matt Wagner probably thought a black shirt was a little too much empty space and wanted Kevin to look a lil' super-heroy and was reading a Shazaam book at the time.