Originally Posted by
CM3
Q: Archer's greatest defense is "Rho Aias", but if he were the same person as Shirou, shouldn't his greatest protection be "Avalon"? In the Rin route, Archer knew that the holy sword's sheath was inside Shirou, so wouldn't the Heroic Spirit form of the Shirou that "knew" that the sheath was merged with him be Archer?
A: Avalon’s power won't work if Saber's not connected to it. It's a different story during the Grail War, but all it does when Saber isn't around is make Shirou's magic attribute into "sword". Also, after the Grail War is taken apart, the link between him and her will be gone, so it's best to think that his image of "Avalon" also disappeared.