[Knai]

What resources do you have? You mentioned paralyze and soul slay, so I'm assuming fairly good astral access. In which case, at a very low end, you almost certainly have Horror Mark. Slightly higher up, there's the small matter of Stellar Cascades.

However, if you also have other magic, new options open. For instance, Gifts from Heaven may well be your friend (29 protection does next to nothing against it), and if it isn't immune to lighting there is always focused fire lightning spells.

Another method is to use your own SC, that is specialized in killing SCs. What equipment you would use is slightly different, in that you want a single target weapon you can reasonably hit with that does either a lot of damage or has a very nice side effect. If you're dealing with an undead or demon, that may well mean the Flambeau, and if you are using CBM the Gate Cleaver is actually a meaningful contender. If, and this is a big if, you can manage to get your hands on a Hell Sword that would be ideal. One touch, and your SC problem is solved forever.