Warlock – “Expansion” [4th campaign, 2nd mission]

I only captured the first Castle, and Railag already arrived – the limit of development has been reached. Is there any point in upgrading Shadia (I'm so angry at whoever leveled her up to level 10 before me), or is it better to take all the chests with gold? Now, no hero will escape from me – among a pile of artifacts, one red messenger happened to have shackles.