Right next to the Castle, there was a portal leading to a strange underground zone with at least 7 explored exits, probably a doubled central zone, but I didn't find any guards between them. I cleared two exits – leading to a mini-treasury and a consulate, and I was preparing to place Knights on the 7th day, but I had no idea what to do next: the minions were uninspiring, the main area was unexplored, and I couldn't find any artifacts.
On day 116, the opponent, slightly ahead of me, surrendered! GG.