SMUnlimited

It was the only way we could come up with. The perk system does not allow new perks just like that. The whole logic has to be created from scratch.

Supreme magicka creates sneak magic attacks by manipulating the weakness to magic effect on npcs. There is no special gameplay settings I know about that can enable this effect. How this works in supreme magicka when the player is sneaking and is undetected by enemies their weakness to magic actor values are forcibly increased. Once the player has casted their spell and hits the enemy the extra weakness to magic is removed and we display a friendly message that a sneak attack occured.