With my transportation nightmare dealt with, I should have more time to post again.
There is a dramatically appropriate number of Marines, so feel free to kill some off. Just keep in mind that these Marines are basically fleshless constructs bound by incredibly powerful magic, so they are not nearly as easy to kill as normal Marines. Try not to kill swaths of them at once and expect me to post counter-attacks against you that you'll need to take seriously. Also, the chaos fire they're shooting is pure chaos energy, so it can't be controlled like normal fire, and their swords are coated with the same energy, so they will cut through normal armor.
Any questions, let me know.