I'm starting up in Adeptus Titanicus, I play other games a lot and have played a few matches of Titanicus so far to learn it. I bought some models and have assembled them, my friend wants to play as Imperial and so I'm playing Chaos.

I would like to play as a legion that has sided with the Warmaster, not out of wanting to worship Chaos (and they would even be abhorred by it if they knew the full extent of what Horus was about) but rather they see the Imperium as tyrannical and they want to liberate their world. They are noble and their titans have resplendent colours. Is there a legion like this already in the lore/game mentioned specifically? Or should I create my own custom legion? Just checking with those who are more versed in the titan lore.