User blog comment:B214/Question and Answers/@comment-115.133.205.90-20130731171605/@comment-1359322-20130731182140

To be exact, it's when they're leaving the Underworld.

[We had boarded the train and were giving our last farewells to Sirzechs-sama and the others from the window.

Ah—.

At that moment, I noticed. Sirzechs-sama, Millicas-sama, and also—.

I saw two parents and their child in that three-shot. As I thought, it was like that. It wasn’t a joke—.]

{Volume 5 Reunion}