Caliborn is the first person, out of those that we’ve seen, to play SBURB
Calliborn and Calliope both have the program that allows people to talk to others from different points in time, as shown by this pesterlog.
But I’m starting to think that Calliope and Caliborn are playing from the past. The reason being Lord English. We can easily infer that Caliborn and Lord English are the same person, but they aren’t the same age. Lord English looks much older than Caliborn. Also the way Lord English has already entered sessions, it looks like he’d be traveling toward the Alpha kids session soon, something that doesn’t quite make sense if Caliborn entered the game after the Alpha kids like the order the comic gives us.
That leads us to some of the issues with this theory, namely the fact that Calliope/Caliborn live in the meteor the Beta kids and trolls were traveling in and they have access to Rose’s book. This would be a paradox if they were the first SBURB players because these things would have only been created after their existence. However this is not the first time where things created in the future found their way into the past.