Camaysar

"Would you please become my beautiful bride?"

- Camaysar, to every girl he meets, plus Soujiro

 is the Genius of Marriage1. He is briefly mentioned in volume 10, Homesteading the Noosphere, and has his role expanded on in Season 2, Episode 21 of the anime.

Synopsis
Camaysar was capable of disguising himself as a handsome male Lander, and seduced women in Akiba. His true form appears as a snake like humanoid with long sharp talons and grey scaly skin and large red eyes which he uses to hypnotize his victims. However, once he started targeting West Wind Brigade members, he incurred the wrath of Soujiro, and the West Wind Brigade ends up killing him. Notably, he ensnared Sara, raising the suspicion of the guild and the direct animosity of Kurinon.

Trivia

 * In Transcendental Magic, the book that the Genius and their epithets are derived from, Camaysar is the Genius of the Marriage of Contraries.