Final battle in vortex campaign

Playing as Jagsmarshall in the vortex campaign I find almost impossible to win the final battle. Has anyone achieved it ? When I lose, on the lose screen I see another army next to mine, as if I had reinforcements. But I didn't get any. If I had this reinforcement army I could have won that final battle. Do I miss something ?

https://www.aht.li/3642793/20210822232106_1.jpg

I found the solution to win the final battle, you just have to use the special hunters heroes. Each one has a unique effect in that final battle, and one of them makes reinforcements come, which makes that battle much more easier.