Mire, like most slimes, finds human clothing to be uncomfortable. The challenge of keeping the fabric from sinking into her form is more than she would like to deal with day-to-day. For this reason, the school allows her to roam naked with the stipulation that she cover herself walking to and from school. Also, like most slimes Mire fears dissipating into the pool water on campus. Which is how she ended up in Manga club; No liquids allowed in the club room.