I've worked seasonally in a nursery for three years now and I'm about 95% sure the Demon Rose is a De La Grifferaie. They're leggy, got huge-ass thorns and are extremely cold-and-pruning-and-poison resistant. Normally not quite as neon pink but that color indicates she's really happy where she is. If it makes you feel better, they're particularly good for a lot of Native Wild Bees, and any further attempts that are not actually illegal are doomed. Enjoy your immortal rose!
Looking that up on google I’d say that could sound about right, were it not for the fact that it says the roses are highly scented and Demon Rose has little to no scent at all. But perhaps she’s the bastard off spring of that and something else.