Chu Mu wanted the Demon Tree Warrior to take action precisely because there was still a month of buffer time. Chu Mu had a level 10 Wood Element Soul Crystal, and since the disasters were so concentrated this time, the Demon Tree Warrior could get a lot of practice. Chu Mu planned to have the Demon Tree Warrior play a primary role in this battle, and immediately attempt to strengthen it afterward.
If the Demon Tree Warrior could reach the Peak Monarch level, Chu Mu's chances of eliminating tribes would be even greater.
There weren't many commander-level legions, with about 150, but most of them were tenth-rank commanders. If they were high-level monarchs, their combat power would be equivalent to Chu Mu's previous ninth-rank monarch, and they're definitely a group of legions not to be underestimated.