Ok theory time.

So you all know this picture, right?

I have a theory.

Undertale was created on September 15, 2015.

It says that the Human-Monster War was in some time during 20XX.

So the Sanses were all made in technically 2015, but everyone makes the Sanses (depending on the AU) around a teen to an adult (mine is around teens).

But...

If they were born before the war, and the war was in 20XX...

This would make the Sanses Gen Z.

Let me explain; Gen Z is anyone born from 1997-2015. Right?

So this would mean the Sanses were born sometime during this period, making them Gen Z.

Oh the power this gives me