Few Inquisitors start out adhering to this faction, as most radical doctrines embody such drastic ideals that a newly ascended Inquisitor would probably denounce them as outright heresy, ignorant as even he is of the full horror of the galaxy. Even if an Inquisitor of a Radical faction has selected one of his own Acolytes to become an Inquisitor, he is unlikely to reveal his true leanings until such time as his disciple has trod the path for himself, though a master might subtly guide his protégé along the way.
Though the specifics vary enormously, one point that unites many Radical doctrines is that little, if anything, is held as sacred. A Radical Inquisitor regards himself beyond all law and above reproach, and while this is technically true of all Inquisitors regardless of their leanings, Radicals take it to the extreme. They pursue researches and teachings held as forbidden by other Inquisitors, especially those of a Puritan leaning, in the belief that they and they alone have the strength of will to resist any dangers such pursuits engender. A Puritan might hold that contact with the alien is forbidden and even an Inquisitor should hold no truck with them; a Radical might reason that such small-mindedness denies humanity valuable opportunities, seeking to learn the secrets of the xenos and even to take up alien weapons. Sometimes the Radical seeks to turn those weapons against the alien that provided them, while at other times he seeks knowledge not known to Mankind at all. While ultimately the Radical might seek to scour the very stars of the taint of the xenos, he is quite prepared to bide his time until the time is advantageous.
At the very extremes of Radicalism are those all but cast out by their peers who act, or at least appear to act, against humanity itself. In all likelihood, such Inquisitors still regard themselves as acting in Mankind’s ultimate interest, even if they appear no
different from its most terrible enemies. Some Radicals prove unable to resist the taint of Chaos or whatever other fell powers they court and do in fact turn to the service of Mankind’s enemies. Even these are still Inquisitors; unless moved against by their peers, they are still willing and able to wield the power they were granted when first they ascended to that position.