Alcázar (アルカサル Arukasaru ) is "Knitter of Thorned Gate" Cecilia Rodrigo's Power of Unrestraint. It is a defensive-type spell which allows Cecilia to strengthen objects by entwining them with her non-substantial leaves and branches.
The leaves and branches created by Alcázar can increase their density and power by devouring the enemy's Flame. They demonstrate their defensive power by forming an invisible cage-like shape to surround the target. Only a stronger power will be able to destroy this untouchable wall, as escape by the earth and sky being futile. Alcázar is very powerful and effective in combat, but requires considerable time to set up.
When Cecilia requests the assistance of Outlaw to defeat Ōnamuchi who is found in the forest of Austria, the Flame Haze of Nietono no Shana is sent to help her. Leaving the Flame Haze to engage her nemesis, she casts the spell to contain both of them. However, Alcázar could only stall Ōnamuchi for a while as he eventually manages to break free from it and continues pursuing her.
- An Alcázar is a type of castle in Spain and Portugal. "Alcázar" literally means "castle" in Spanish and is derived from "residence of the king" in Arabic.