Like... Most of them, I would say. Technically speaking, anyone who's stronger than Malistaire the Undying (Xibalba version) should have some form of immunity over magical attacks at least (other things such as statistics reduction and the like worked on him, but they were still 0 damage), and that's after factoring in the player's resist negation. As for who counts as stronger than him, that would be pretty much anybody with Shadow Magic at a basic level, which Spider obviously has and at a much greater extent than everyone else.
There are also certain characters which have really absurd shielding abilities, which again negate the Player's resistance negation (this time after Shadow Magic comes into play). To put it into perspective, 100% resist/shielding is considered full immunity to damage, and these characters have -999% shields. They would be completely protected even if the player cast their Scion spells alongside every resistance-negating spell/buff at their disposal.
This is without going over Omnegation/Dispel All which pretty much negates every hax on Spider's profile.