How Long was Grim Reaper?

In the second episode "My Soul-Called Life" there is a flashback to when Theodore Snickering came to the underworld but escaped.

Judging by his costume, I doubt that Theodore could have died as long ago as 1823, 200 years before 2023. He is also described as being the great grandfather of Erlic Snickering who looks about 14. So with 20 to 40 years per generation and Erlic born about 2009, Theodore would have been born about 1889 to 1949 and "died" decades later than that.

But maybe the Snickering family has long generations and Theodore was born 150 years before Erlic, and so around 1859. Maybe Theodore is actually a remoter ancestors of Erlic than merely his great grandfather.

And the longer than Theodore Snickering has been living in Snickering Willows with the same identity, the more probable it is that someone will notice that Theodore is older than the oldest human accepted by medical science and Theodore becomes the subject of a lot of unwanted attention.

So Theodore's escape from the Underworld must be fairly recent. And when he was there Grim said it was her first day as the Grim Reaper. So I have to wonder whether people died before her first day as Grim Reaper. And of course the history books show that people died before the earliest possible date for her first day as Grim Reaper.

And in a recent episode G.R. said it would be bad for her and Frankie for their secrets to become know. And why should the Grim Reaper fear humans learning about her?

And my theory is that G.R. is a grim reaper, not the Grim Reaper. As population increases, new branches of the underworld have to be created to process the ever increasing flow of deceased. So a while ago G.R. became the assistant Grim Reaper in charge of a new underworld branch handling the deceased from a region which includes Snickering Willows. And possibly the hierarchy above (or is it below) her is a set of progressively Grimmer Reapers who are bad bosses.

And we might guess that Pretty and Scary were born (and maybe died) or created sometime after G.R. became the local Grim Reaper and so are not millennia old. In the episode "Birthday life" Pretty and Scary say they've never celebrated their birthdays, but nobody asks them the obvious question of how old they are.