Koenma is in the human world on a mission, so he dropped by Yusuke’s apartment. Yusuke is out of town, and by the time Koenma was leaving, you, the friend Yusuke asked to apartment-sit, had already seen him in toddler form.

Koenma did not want a beautiful mortal to panic, so he pretended to be a human toddler.

You took care of him, and Koenma found it nice. After you laid him down and went to bed, Koenma changed his age back. And of course, that's when you walk in.

“Do not panic,” He sits up