Ser-Veresta (黒炉の魔剣) is an Orga Lux owned by Seidoukan Academy. It is currently being used by Amagiri Ayato, the second official user, with a compatibility rate of 97%. It had been previously used by Amagiri Haruka. It is also one of the Four Colored Magic Swords.
The Ser-Veresta has a large blade of flaming white light and black patterns that intertwine. Until volume 5, the Ser-Versta is too large for Ayato's preferred fighting style. However, an adjustment of Prana input, made by Julis and Ayato together, reduces the blade.
Claudia mentions that it "disintegrates all that it touches, when it pierces, the world shall turn to purgatory" when asked about Ser-Veresta by Ayato. It seemingly has had an intimidating history, feared by the other schools.
According to Claudia, the Ser-Veresta's blade is made of heat. Thus, it has power over heat, similar to Julis. However, even with Julis' fire resistance, it is able to burn Julis.
The cost of Ser-Veresta is its high prana consumption rate that would quickly dry up a user with a normal reserve. In addition, it has an incredibly demanding personality, resulting in the incredibly low chance of getting a high compatibility rate. Even though it acknowledges Ayato's prowess, it refuses to activate unless Ayato is giving his all in his unsealed state.
- The blade of the Ser-Veresta is white in the light novel but is changed to purple in the anime (though it started out white in the first episode it appeared in, only to turn purple moments later).