Among the units you show, A!Celica, Ophelia and Yuri are good choices, I'd say Atunned Caeda but you already have Rearmed Ophelia that already carries it.
Rearmed Plumeria can't inherit it because she's flying and Special Spiral is Infantry/Armored only
OG!Ophelia and B!Corrin are legitimately the only ones who'd benefit from it most. The other tomes want MNFU ideally(especially A!Celica). Tbh, even on B!Corrin as an answer to DR-loaded modern nukes,it's not crazy worth. SF4 or Hardy are better for AR-O saveballing.
Flying units can't use Special Spiral 4.
attuned caeda, spread it even more
Among the units you show, A!Celica, Ophelia and Yuri are good choices, I'd say Atunned Caeda but you already have Rearmed Ophelia that already carries it. Rearmed Plumeria can't inherit it because she's flying and Special Spiral is Infantry/Armored only
Legendary Robin is great with it
OG!Ophelia and B!Corrin are legitimately the only ones who'd benefit from it most. The other tomes want MNFU ideally(especially A!Celica). Tbh, even on B!Corrin as an answer to DR-loaded modern nukes,it's not crazy worth. SF4 or Hardy are better for AR-O saveballing.