Yunyun became very jealous of Megumin after the latter spent so much time possessing others with Kazuma. Reluctantly, she agreed to be their next target.
Due to her timid personality, Kazuma swiftly took over her mind not long after the possession process has started and began modifying her body to his likings. Although Yunyun's physics back when she was first possessed was already very beautiful, Kazuma had a way to make it even better. With Megumin's body also inside of her, he began adding Megumin's body mass to her body until she resembled a 6-feet-tall woman in her 30s. Now, Kazuma will definitely enjoy the body of this motherly version of Yunyun.