"The Knight is an excellent melee specialist. However he doesn't know how to use ranged weapons..."
The Knight is a hidden character for Strike Force Heroes 3. The default weapons for this character are two knives. There is only one Knight in the game, going by the default name of Rusty.
The Knight's symbol is two semi-circles. The top one is a half-sun, the bottom one being a half gear.
Rusty can only be unlocked through an easter egg; on the Campaign screen (After having obtained the Base Expansion for completing the third mission), at the bottom there is an advertisement for Knight's Quest: Spirit Shield. To the right of the advertisement, there is text that reads "New! Knight Hero". Clicking on this text will give the "Unique Hero unlocked" message for the Knight class. After doing this, go to the Heroes tab and recruit a new Hero; it will be Rusty, the Knight.