After much frenzied typing, I've finally finished creating a new villian for the Antona Australis Sector: Germax Sahawat.
You can read about him and his quest to resurrect his murdered family in the link above. My main objective was to give the sector a character that coul serve a similar function to Eramus Haarlock in the default Dark Heresy (1st edition) setting - acting as both an overarching threat and as a seed for all manner of dark inventions and artifacts and help make House Temporis (my home-brew Imperial Knight Household) appear rather dark. I'm in the process of relocating it from the Calixis sector to Antona Australis, and they were originally involved with Haarlock, so I needed an equivalent.
While Haarlock and Sahawat have very similar motivations, I've tried to make Sahawat sufficently distinct from Haarlock - blending in elements of gothic fairytale, Disney (there's more than a dash of Geppetto), Dr Who and Moriarty. Liberal helpings of Nagash and Vecna (of D&D fame) have also gone into his creation, but I hope that he stands up in his own right.
The Dark Eldar get a fair bit of screentime and this is deliberate - I wanted to create a tie to Lord Blood's excellent Coven of the Perfected Flesh and to highlight the extent to which his talents elevate Sahawat above a typical human in this setting.
Astute readers may be wondering who or what prevented Germax from simply going back through time and saving his family. Let's just say that I have a very good idea - the Ordo Chronos is not the only faction to be observing his 'career' with interest.
I have made his power-level deliberately high - as befits someone who is more likely to serve as a plot device rather than be confronted in person. That said, I am tempted to create a miniature of him, together with some suitably macabre clockwork hangers-on.