I don't think the Fallen ever had actual Guardians. That's one of the things that makes them hate us. The Traveler visited them, shared technology with them, terraformed planets with them. Just like he did with us. But the Traveler never shared the Light itself. Not with us before the Collapse, not with them. The Traveler created Ghosts after the Collapse. After Rasputin forced Alpha Lupi to fight. To unleash all its Light and nearly destroy itself. I think that's when the Traveler created the Ghosts, who created the Guardians. As a measure of protecting itself, since the Traveler is too weakened now. We never had that Light before the Collapse, and I doubt the Fallen had anything like it before the Whirlwind. The Fallen look at us and see the Light the Traveler shared with us, in a way it never did before with them. It's probably one of the things that makes them hate us. It saved us, when it abandoned them, not knowing that it tried to abandon us as well once. They see us as Ghouls, hoarding over the Great Machine that might have once saved them. We are dead things, created by a dead power, and that is what we bring in our wake.