|Clarent Blood Arthur|
|Title:||Rebellion Against My Beautiful Father|
|Owner:||Saber of Red|
|Maximum number of targets:||800 people|
Clarent Blood Arthur: Rebellion Against My Beautiful Father (我が麗しき父への叛逆, Kurarento Buraddo Āsā: Waga Uruwashiki Chichi e no Hangyaku?) is the full power released form of Clarent utilized by Mordred as her most powerful Noble Phantasm. Upon utilizing it, she takes a stance, while at the same time, her helmet, Secret of Pedigree, is removed. It cannot be activated unless the helmet is removed, so she is forced to do so when she wants to utilize it. The space around her and the sword becomes stained with blood, and the blade of the sword, enveloped by the radiance of blood, gives off strange sounds and begins to transform.
The appearance of the Noble Phantasm is not that of the pure, beautiful, and famous sword, but a sinister and wicked blade fit to be wielded by a demon, transfigured by her wanton hatred. Dyed with dark blood and warped into an unsightly form, it becomes a demonic sword of calamity. Raising the grotesque sword clad in her hatred, she releases the blood radiance upon the enemy, and it is released as a flash of light, a surging wave with the simple purpose of destruction. It releases a straight line of crimson lightning from the tip of her sword, very similar to Excalibur, but differing from the semi-circular blast of Balmung. Utilizing it takes a great deal of energy, giving her intense pain throughout her body, but her Master's competency allows her the strength to move immediately after utilizing it.