Grima's a villain, as is Malvina, and Malvina's torture subject is unlikely to be one.
Malvina being utterly wrong for the Clans and whatever else has nothing to with purity BTW. It has do with the fact she's wasteful, petty, vindicative, mad, stupid. Very, very much like Stefan Amaris (though to his credit, Amaris was sane for most part).
Sure, she is terrifying at the moment, but that usually doesn't form a good foundation for future empires. Gonna be a short reign, if there's even one.
She had the idiotic idea that if she loses, she nukes Hesperus II. Doesn't make much sense... especially since there's a breaking point when her opponents start throwing WMDs back at her, and i figure losing Hesperus factories would've been one for the Lyrans (and i think everyone else would've followed suit).
There is no future with Malvina, only destruction. The early Succession Wars, the Jihad, and the Wars of Reaving were the result of Malvina-like thinking. All folly, all wasteful, with nothing gained for whoever started these.