Before, Silas advise him to put the ten thousand troops under Lord Aleister, Silas has secured the support of the other noble lords that he is sure not involved in the alliance,
under his name, Silas has been sending them letters to show their loyalty to the throne of Arakath by protecting the King when the time comes
And to complete that plan, before this battle, he has planted some spies in the ten thousand troops sent to Lord Aleister and bribed several of Lord Aleister allies to not show up for battles.
Silas also said that not all lords know the true intention of Lord Aleister conspiracy and most of them follow him was seduced by Lord Aleister promise of gold and riches
Lord Aleister must believe that the other nobles did not show up because he needs to show first that he can win this first hurdle.
It was at this time Azrael look at Silas with trepidation. The planning and the subterfuge he employed fills him with amazement.