timebend
this is gonna be some real bullshit.
Lathrop Stokes is a chronurgist articifer who invents the Temporal Funnel. (or fuck it, enrique is a portal tortle)
Lathrop's warnings:
The temporal funnel works by "bending" time around you so that your "now" touches a previous point in the timeline, from which point you can progress forward back to "now" again.
Kind of like a paper fold-in like in Mad Magazine. Sort of.
Anyway, so time only ever flows forward. You can't change history, and you can't change the future.
What you can do is gather information, create situational advantages, plant things, etc. You can make changes that don't effect memories / recorded history: if nobody remembers something not happening, then you can probably do it. But you can't do something wild that you would definitely remember having happened.
You can enter the funnel at some time x2, and will always exit the funnel at the same time, x1, which is probably when the funnel was invented. The trip "backward" from x2 to x1 is still forward time, it's just going forward through the bend. Once at x1, the bend will straighten out again and you'll continue "forward" once more toward and past x2.
everybody knows that birds are the original time travelers
they created the Original Paradox by attempting to travel back in time to visit their ancestors but something went horribly wrong, and that's why diverse bird populations predate feathered dinosuars (true story).
ever since then small birds, barn swallows mostly, have flocked to time travelers and swallow up paradoxes as they occur.
guardians of the time stream
according to our own rules we cannot change the future.
which means that we can't time travel to prevent a successful ritual.
so in order for this to work narratively, the ritual if successful must kick off a countdown or something. "The Blood Prince will break through to our realm in 3 days! You can do nothing to stop it! Evil laugh!"
question: what can you do in ~2 weeks to stop the arrival of the blood prince that you can't do in 3 days?