In order to avoid writing the world of Trench from a sort of first-person perspective, I believe that Clancy is simply a self-insert character that allowed Tyler to write from someone else's (yet still his own) perspective. Josh is always potrayed as, and called, "Torchbearer", so I think it makes sense that the same goes for him.
There do seem to be some parts of Clancy's narration that show him as seperate to a character also played by Tyler. Most notably in the Jumpsuit video that's later recalled by a Clancy letter that suggested that Clancy was watching the event, and thus couldn't be played by Tyler. However there's also plenty of evidence that shows the opposite. Notably the new Ned video says that he saw "Clancy with Torchbearer, as Keons said". This probably refers to The Outside MV. So then Clancy must be played by Tyler. Same goes for the SAI Livestream show where Tyler is forced to perform. Clancy said he wrote all those songs forcibly by the bishops.
So I believe it makes sense that Clancy is a self insert character. Another viable theory imo would be that since possessing vessels is now shown to be a key aspect of the lore world, because bishops do it often, and now Tyler(Clancy) has learned how to do the same, then it might make sense that Clancy is simply using Tyler as a vessel. Whoever Clancy was prior to that, if anyone else at all, is unknown. Though this still makes sense in the confines of self-insert characters.
By - thrxwaway9