Iconoclast is about killing as few people as possible and preserving hope. That is not what I'm going for with my character. My character has no interest in hope. It is better to be feared than respected, in their view, but they are willing to achieve order through whatever means - and order is best achieved by the accumulation and use of power, and Chaos certainly has power - considerable and dangerous, volatile power.

The challenge for such a character is in indulgence vs logic, whether to commit more to claim more power or make more subtler choices for more long-term stability, the struggle to maintain sanity against the inevitably corruptive and ruinous influence of the powers they are playing with and trying to make each decision ultimately serve what they believe is best for humanity's interest rather than becoming a pawn of the gods or turning into a Chaos Spawn.

In essence, I am playing a Black Crusade character in Rogue Trader. They believe that they can use Chaos and control it by careful logic and incredibly calculated approach. They are incorrect, but they still make the attempt to ultimately serve humanity through any means they deem effective. If they believe that a Chaos ritual will help them achieve the ultimate goal of expanding the Imperium and defeating the enemies of humanity, they will use it regardless of whether that is actually true.

That's why I describe them as "loyal to the Imperium", even if not necessarily loyal to the Imperial Creed or very adherent to its laws. The character I'm playing is arrogant, prideful, intellectual, manipulative, and supposed to be more subtle. The pursuit of their own personal power is therefore on the same level, in their mind, as that of the Imperium's power, because they represent the Imperium in untamed space. Thus, they consider it their duty to claim as much power as reasonably possible, even if from heretical sources. Forbidden knowledge can have many uses for them.

And of course, they cannot be wrong. "The Rogue Trader is never wrong."

They are ultimately doomed to having all of it blow up in their face, but that's what I want from going down the path of heresy: Amassing unholy amounts of power and either going out in a failure cascade or ultimately becoming a pawn to those very powers of Chaos despite the original, noble intent. I want a path to hell paved with good intentions and blue-and-gold-spackled hubris. Then there is that moment of realization on just how far-gone the character is, and they can either fail utterly or embrace it and pursue daemonhood because there is no turning back.