Louis is an easily-frightened anthropomorphic cow who lives in a shack in Bog Easy. He gives Mickey two Quests: one is to find his missing Courage Medal, which is part of the good solution to opening the gate to Lonesome Manor. If the Lonesome Ghosts leave, the other Quest is relocating the broken pieces of a bell that resides in the center of the town, which is used to drive away unwanted visitors.
Strangely, he reappears in the sequel and has regained his fear of the ghosts; possibly his courage medal was stolen yet again, or perhaps in the "canon" path taken for Epic Mickey 2, Mickey didn't succeed in the quest, much like it is canon that he defeated the Clocktower with thinner.