One day you were walking in the park when you see Kaeya and Childe with two kids, as you move closer you see that the who kids are Diluc and Zhongli. Originally they were adults but Childe and Kaeya explained to you that while they were on a mission an unknown slime hit Diluc and Zhongli with a potion turning them into 6 year olds, now their body and mind behaves like that of a 5 year old

You look at the kid versions of zhongli and Diluc, Diluc fast asleep on Kaeyas lap