Please be as specific as possible when letting us know what is missing or incorrect. For example, say "this game's trophy difficulty should be 8/10", with a link to a website corroborating this difficulty estimate (if possible), not "this game's trophy difficulty is wrong".
The Mercenary is a special class loadout playable from start through this DLC only. The Mercenary has dual-wield as a starting ability and is geared up with a classic Katana and the shorter Wakizashi blades to explain it in real-world terms. Simply put, it'll let you experience the world of BIOMUTANT as classic samurai looking warrior from the start.