Quixos

Quixos was a radical of the Ordo Malleus who decided the Eye of Terror was an engineering problem. Daemonhosts Cherubael and Prophaniti did the heavy lifting. A daemon-sword ate Kharnagar. Cadia's pylons were the template. Farness Beta was going to be the prototype that slammed the Eye shut if you ignored the cost in psykers.

Eisenhorn spent Malleus becoming the kind of Inquisitor who could reach him. Other inquisitors died in the mountain. Quixos still had enough left to call Eisenhorn heretic while the broken force sword finished the job.

His ashes were a warning label the Ordo still argues about. Close the Eye, lose the soul, pick one.