Avalon Syntax

Sacred Arts (神聖術, Shinsei-Jutsu, lit Holy Arts), also known as Magic-Knight Techniques. These are specialized combat techniques that Lancelot developed using his natural abilities: Aura (ki), Magic and Light abilities.

Summary
Introduced in Volume 6 on two occasions, one being when Lancelot activated a unique magic circle to nullify the attacks from a stray devil. Second being during a practice match with Jeanne.