There is a quest known as The Restless Lion in ep 4 one player mode, in which you fight other npc hunters and, uh, "liberate" their weapons from them. They're highest tier weapon and highest special and spawn with two 50%s and 0, 30, or 50 hit, so it's possible to get a King's Striker from that quest. You can also hunt stuff like Hell Laser or Arrest Raygun or Charge Vulcans or other such things. This quest is also why everyone's dark weapons are at least triple 50%, they farm the base weapons from here.