This rather volatile young man is a former member of the Followers of the Apocalypse. He's a stubborn blockhead and loathes religion of all sorts. Even though the New Canaanites are doing pretty well, he can sense a general dislike and/or distrust of Jeremiah Rigdon. He believes that Jeremiah should be overthrown and all the current residents of New Canaan should be allowed to vote for a leader democratically.
He compares New Canaan with Vault City which is, of course, completely unfair. He wants to do this violently, through the assassination of Jeremiah. Steve is a man of average height, fair skin, and short, dark hair.
Get Bulk Gun Parts for Steve: Steve needs gun parts specifically because of the policies regarding weapons in New Canaan. To successfully acquire guns he'll need to use the parts to reconstruct them. The Prisoner could presumably obtain most, if not all, of these parts from Jacob, as his "junk" consists mainly of various pieces of disassembled weapons and armor.