Impressed with how you're able to take on one foe at a time, Kane wishes to test your multi-tasking ability. He has ordered Nod, Black Hand and Marked of Kane forces to face you in the Australian Yellow Zone. To prove your worth to Kane, simply defeat all three.
You will be able to pick any of the 9 sides upon starting the challenge. Pick your favourite, or challenge yourself even further by picking your weakest (sub-)faction. Depending on difficulty, you will have plenty of time to build up and prepare for Nod's assaults... so long as you don't provoke any of the three first.
Be warned: as the sub-factions join the battle, they will provide the main Nod army with additional unit options and upgrades.
IMPORTANT: This challenge crashed for me on Kane's Wrath v1.03 during almost every playtest, even when saving straight away. However, players have reported that the challenge didn't crash for them on v1.03. Please let me know in the comments if this challenge did or didn't crash for you.
I know about the missing text, there is nothing I can do about it as it an issue with how Kane's Wrath Worldbuilder uploads to Steam Workshop.