Genius Bonus: The runes used in Chaos spell effects is deeply evocative of the Furthark script. One is even exactly like the sowilo rune. Another is exactly like Ingwaz. There's also a bit of the Anglo-Saxon script in it also. Makes sense, the guys who serve Chaos are Vikings and their leader's called Thorgar.
Spiritual Predecessor: The game can be seen as one to the later, and much more successful, Total War: Warhammer series. With both games sharing the same basic concepts, albeit with a more linear focus on the part of Mark of Chaos.