It was called Filagreed Chains by Brthanes and it was archived on the old Bloodshedverse but the tlink no longer workd and using the wayback machine is no help. It is a wip that had a great Spike timetraveling into the past after NFA with Illyria and Spike setting up a demon Initaive type thing except the Initative soldiers weren't experimented on (rather they were cured of the drugs put into thier systems and the chips) and were treated extremely well which confused them no end.

Try it here

Thanks!

I've been wanting to reread that for a while.