A Special Ability (特殊能力 Tokushu Nōryoku ) is a Crimson Denizen's original ability and essence.
Sorath's "Olfactory Sense of Desire" (欲望の嗅覚 Yokubō no Kyūkaku ), Tiriel's "Doting Embrace" (溺愛の抱擁 Dekiai no Hōyō ), and Vine's "Contagion of Perception" (知覚の伝染 Chikaku no Densen ) and "Shikai Kakuran" (視界撹乱, Vision Disturbance) are examples of Special Abilities.
They are classified as Unrestricted Spells. However, they are not stylized by the user like Fūzetsu is. The Special Ability conforms to the essence of the user's existence, and thus can't be used by anyone else.