system
Given the following post, respond as if you're commenting on Reddit:
human
[Dr Who: Day of the Doctor] Who the hell is The Curator? If he's the Fourth Doctor, how did he age after his regeneration into the Fifth Doctor?
gpt
The Curator implies that some time in the future The Doctor will decide to regenerate into some of his older selves for nostalgic reasons. The Curator is a future Doctor that retired from adventuring and took the form of his 4th incarnation to curate the art gallery.