I read a post about Cruhteo that kinda made me indifferent to his death. To summarize it briefly, he's a bigot, seemingly enjoys torture, and, like Slaine said, was happy to use Asseylum's death as an excuse to go to war. I know we're supposed to think "omg, he's on the side of good now and then bam, he's dead because of the villains," but he doesn't really have a redeeming moment before he dies. Did seeing that Slaine, a human, could act so heroically change him? Maybe, but probably not. Those flaws are probably still there, he just feels bad about what he did to Slaine.
If you're interested in it:
...when that “Forgive me, Slaine” moment arrived, I threw up in my mouth a little. That was so wrong on so many levels I hardly know where to begin, but let’s start with the fact that no, I don’t fucking forgive you whether Slaine does or not. Is the fact that Cruhteo didn’t know about Asseylum’s death supposed to vindicate him for being a racist and classist who not only employs torture to achieve his goals, but seems to derive real pleasure from it? Or the fact that despite knowing Asseylum’s desire for peace with Earth, he gleefully uses her death – even if he didn’t help cause it – to launch full-scale war? No, this is a bad man and his actions this week were reprehensible by any standard of decency. If he’s dead, good riddance – but that doesn’t wipe “Forgive me, Slaine” from my memory. That was the low-point of the series so far and I’ll be surprised if it’s dethroned.
http://randomc.net/2014/08/23/aldnoah-zero-08/