Ishmael is a college student and a character in the Martians theme. He does not particularly like the Martians, but he did help them with their invasion during the 2007 Martian invasion of earth. (Although bribed with brownies.) The Martians are led to believe he is an elite warrior because he plays Half Life 2 (as seen here).
Ishmael claims to be owner of a Cheshire Cat which appears with him in some strips but was revealed during the End of the Universe story arc to be a time-traveling Cheshire Cat and is seen chasing a rat through all of the themes in Irregular Webcomic! except Supers