Ms. Mercer, only level 12, faces a level 20 dungeon challenge with limited skills. Suddenly, she transforms into 'Mr. Rot,' a powerful zombie form with instant kill ability. As she advances, she reaches level 20, unlocking her third evolution: the Green Zombie with a toxic Poison Miasma skill that devastates enemies except her party members. Using this new form, she clears mobs effortlessly, surprising allies and enemies alike. Despite her awkward green appearance, her strength changes the battle, but the consequences of her toxic power on others outside the party remain uncertain.