Devolik
Auto-translated
No, it's not a viper. All armies on the map grow larger each week, including the neutral ones. So, your pace of the game affects not only the computer's army but also the neutral armies.
Regarding the trial, I don't remember. It seems like nothing special happens; then, they will become available, and your brother will be there. You'll fight with him, and the trial will be completed. Although, I might have mixed up a lot of things in my head.