D. Éclair, Harvar

Harvar is Ox's weapon and takes the form of a lance. In weapon form, he has the power of lightning. Like Ox, he is named after a university (in this case, Harvard). His last name is derived from the French word for lightning. Like most weapons, he can change a part of his body into his weapon form; in his case, he can turn one his hands into the point of his lance form, as well as generate an electric charge through an unchanged hand. As evident during the infiltration of the Arachnophobia castle, he is fiercely loyal to Ox and prioritizes his safety above all else while maintaining an ice-cold composure in battle even when Ox does not.